{ "openapi": "3.1.0", "info": { "title": "tannerd.net Free Public Calculator API", "version": "1.2.0", "description": "Free public read-only deterministic calculator API for humans, AI agents, automations, and MCP/A2A/WebMCP clients. No API key is required. Every result includes a human-facing source and share URL when applicable.", "termsOfService": "https://tannerd.net/terms/" }, "servers": [ { "url": "https://tannerd.net", "description": "Production" } ], "externalDocs": { "description": "Human-readable API documentation", "url": "https://tannerd.net/api/" }, "paths": { "/api/v1/seller-profit": { "get": { "operationId": "seller_profit", "summary": "Seller profit, fees, net proceeds, ROI, margin, break-even price and target-ROI buy price.", "description": "Seller profit, fees, net proceeds, ROI, margin, break-even price and target-ROI buy price. Human source: https://tannerd.net/tools/resale-profit-calculator/", "parameters": [ { "name": "sale", "in": "query", "required": true, "schema": { "type": "number" }, "example": 200 }, { "name": "buy", "in": "query", "required": true, "schema": { "type": "number" }, "example": 50 }, { "name": "fee_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 13 }, { "name": "fixed_fee", "in": "query", "required": false, "schema": { "type": "number" }, "example": 0 }, { "name": "shipping", "in": "query", "required": false, "schema": { "type": "number" }, "example": 20 }, { "name": "other_costs", "in": "query", "required": false, "schema": { "type": "number" }, "example": 0 }, { "name": "target_roi_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 100 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/ecommerce-profit": { "get": { "operationId": "ecommerce_profit", "summary": "Order-level ecommerce profit after COGS, shipping, fulfillment, fees and advertising.", "description": "Order-level ecommerce profit after COGS, shipping, fulfillment, fees and advertising. Human source: https://tannerd.net/tools/ecommerce-profit-calculator/", "parameters": [ { "name": "price", "in": "query", "required": true, "schema": { "type": "number" }, "example": 80 }, { "name": "cogs", "in": "query", "required": true, "schema": { "type": "number" }, "example": 25 }, { "name": "shipping", "in": "query", "required": false, "schema": { "type": "number" }, "example": 6 }, { "name": "fulfillment", "in": "query", "required": false, "schema": { "type": "number" }, "example": 3 }, { "name": "fee_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 3 }, { "name": "ad_cost", "in": "query", "required": false, "schema": { "type": "number" }, "example": 18 }, { "name": "orders", "in": "query", "required": false, "schema": { "type": "number" }, "example": 100 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/break-even-roas": { "get": { "operationId": "break_even_roas", "summary": "Break-even return on ad spend and maximum cost per acquisition.", "description": "Break-even return on ad spend and maximum cost per acquisition. Human source: https://tannerd.net/tools/break-even-roas-calculator/", "parameters": [ { "name": "aov", "in": "query", "required": true, "schema": { "type": "number" }, "example": 80 }, { "name": "cogs", "in": "query", "required": true, "schema": { "type": "number" }, "example": 25 }, { "name": "shipping", "in": "query", "required": false, "schema": { "type": "number" }, "example": 6 }, { "name": "fulfillment", "in": "query", "required": false, "schema": { "type": "number" }, "example": 3 }, { "name": "fee_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 3 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/shift-pay": { "get": { "operationId": "shift_pay", "summary": "Paid hours and gross pay for one normal or overnight shift after an unpaid break.", "description": "Paid hours and gross pay for one normal or overnight shift after an unpaid break. Human source: https://tannerd.net/tools/shift-pay-calculator/", "parameters": [ { "name": "start", "in": "query", "required": true, "schema": { "type": "string", "pattern": "^([01]\\d|2[0-3]):[0-5]\\d$" }, "example": "13:30" }, { "name": "end", "in": "query", "required": true, "schema": { "type": "string", "pattern": "^([01]\\d|2[0-3]):[0-5]\\d$" }, "example": "01:30" }, { "name": "break_minutes", "in": "query", "required": false, "schema": { "type": "number" }, "example": 30 }, { "name": "hourly_rate", "in": "query", "required": true, "schema": { "type": "number" }, "example": 20 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/overtime": { "get": { "operationId": "overtime", "summary": "Regular hours, overtime hours, overtime rate and estimated gross pay.", "description": "Regular hours, overtime hours, overtime rate and estimated gross pay. Human source: https://tannerd.net/tools/overtime-calculator/", "parameters": [ { "name": "hourly_rate", "in": "query", "required": true, "schema": { "type": "number" }, "example": 20 }, { "name": "total_hours", "in": "query", "required": true, "schema": { "type": "number" }, "example": 45 }, { "name": "threshold", "in": "query", "required": false, "schema": { "type": "number" }, "example": 40 }, { "name": "multiplier", "in": "query", "required": false, "schema": { "type": "number" }, "example": 1.5 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/trip-cost": { "get": { "operationId": "trip_cost", "summary": "Gallons, gas cost, toll-inclusive trip cost, cost per mile and split cost.", "description": "Gallons, gas cost, toll-inclusive trip cost, cost per mile and split cost. Human source: https://tannerd.net/tools/trip-cost-calculator/", "parameters": [ { "name": "miles", "in": "query", "required": true, "schema": { "type": "number" }, "example": 300 }, { "name": "mpg", "in": "query", "required": true, "schema": { "type": "number" }, "example": 30 }, { "name": "gas_price", "in": "query", "required": true, "schema": { "type": "number" }, "example": 3.25 }, { "name": "tolls", "in": "query", "required": false, "schema": { "type": "number" }, "example": 0 }, { "name": "people", "in": "query", "required": false, "schema": { "type": "number" }, "example": 1 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/cost-per-mile": { "get": { "operationId": "cost_per_mile", "summary": "Vehicle cost per mile, revenue per mile and profit per mile.", "description": "Vehicle cost per mile, revenue per mile and profit per mile. Human source: https://tannerd.net/tools/cost-per-mile/", "parameters": [ { "name": "total_costs", "in": "query", "required": true, "schema": { "type": "number" }, "example": 800 }, { "name": "miles", "in": "query", "required": true, "schema": { "type": "number" }, "example": 2000 }, { "name": "revenue", "in": "query", "required": false, "schema": { "type": "number" }, "example": 1600 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/gig-profit": { "get": { "operationId": "gig_profit", "summary": "Gig-driving profit and effective hourly earnings after a user-entered vehicle cost per mile.", "description": "Gig-driving profit and effective hourly earnings after a user-entered vehicle cost per mile. Human source: https://tannerd.net/tools/gig-profit-calculator/", "parameters": [ { "name": "gross_earnings", "in": "query", "required": true, "schema": { "type": "number" }, "example": 250 }, { "name": "hours", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10 }, { "name": "miles", "in": "query", "required": true, "schema": { "type": "number" }, "example": 200 }, { "name": "vehicle_cost_per_mile", "in": "query", "required": false, "schema": { "type": "number" }, "example": 0.35 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/roof-takeoff": { "get": { "operationId": "roof_takeoff", "summary": "Roof material planning from footprint, pitch, waste and editable product coverage assumptions.", "description": "Roof material planning from footprint, pitch, waste and editable product coverage assumptions. Human source: https://tannerd.net/tools/roof-material-takeoff-calculator/", "parameters": [ { "name": "length", "in": "query", "required": true, "schema": { "type": "number" }, "example": 40 }, { "name": "width", "in": "query", "required": true, "schema": { "type": "number" }, "example": 30 }, { "name": "pitch", "in": "query", "required": false, "schema": { "type": "number" }, "example": 6 }, { "name": "waste_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 12 }, { "name": "bundles_per_square", "in": "query", "required": false, "schema": { "type": "number" }, "example": 3 }, { "name": "underlayment_sqft_per_roll", "in": "query", "required": false, "schema": { "type": "number" }, "example": 1000 }, { "name": "ridge_hip_feet", "in": "query", "required": false, "schema": { "type": "number" }, "example": 60 }, { "name": "ridge_cap_feet_per_bundle", "in": "query", "required": false, "schema": { "type": "number" }, "example": 25 }, { "name": "eave_rake_feet", "in": "query", "required": false, "schema": { "type": "number" }, "example": 180 }, { "name": "nails_per_square", "in": "query", "required": false, "schema": { "type": "number" }, "example": 256 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/concrete-slab": { "get": { "operationId": "concrete_slab", "summary": "Concrete volume for a rectangular slab with an optional extra allowance.", "description": "Concrete volume for a rectangular slab with an optional extra allowance. Human source: https://tannerd.net/tools/concrete-slab-calculator/", "parameters": [ { "name": "length", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10 }, { "name": "width", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10 }, { "name": "thickness_inches", "in": "query", "required": true, "schema": { "type": "number" }, "example": 4 }, { "name": "extra_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 10 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/contractor-margin": { "get": { "operationId": "contractor_margin", "summary": "Convert contractor markup to price/margin and calculate price for a target margin.", "description": "Convert contractor markup to price/margin and calculate price for a target margin. Human source: https://tannerd.net/tools/contractor-markup-margin-calculator/", "parameters": [ { "name": "cost", "in": "query", "required": true, "schema": { "type": "number" }, "example": 5000 }, { "name": "markup_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 30 }, { "name": "target_margin_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 30 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/square-footage": { "get": { "operationId": "square_footage", "summary": "Rectangular square footage from length and width.", "description": "Rectangular square footage from length and width. Human source: https://tannerd.net/tools/square-footage-calculator/", "parameters": [ { "name": "length", "in": "query", "required": true, "schema": { "type": "number" }, "example": 12 }, { "name": "width", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/time-card": { "post": { "operationId": "time_card", "summary": "Calculate a weekly or biweekly time card with overnight shifts, unpaid breaks, weekly overtime and gross pay.", "requestBody": { "required": true, "content": { "application/json": { "schema": { "type": "object", "required": [ "hourly_rate", "days" ], "properties": { "hourly_rate": { "type": "number", "example": 20 }, "overtime_threshold": { "type": "number", "default": 40 }, "overtime_multiplier": { "type": "number", "default": 1.5 }, "days": { "type": "array", "minItems": 1, "maxItems": 14, "items": { "type": "object", "required": [ "start", "end" ], "properties": { "start": { "type": "string", "example": "08:00" }, "end": { "type": "string", "example": "16:30" }, "break_minutes": { "type": "number", "default": 30 } } } } } } } } }, "responses": { "200": { "description": "Time card result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input" } } } }, "/api/v1/health": { "get": { "operationId": "health", "summary": "API health and version information.", "responses": { "200": { "description": "Healthy" } } } }, "/api/v1/electricity-cost": { "get": { "operationId": "electricity_cost", "summary": "Electricity Cost Calculator", "description": "Calculate electricity use and running cost per day, month, and year from watts, runtime, duty cycle, quantity, and your electricity rate. Human source: https://tannerd.net/tools/electricity-cost-calculator/", "parameters": [ { "name": "watts", "in": "query", "required": true, "schema": { "type": "number" }, "example": 1500 }, { "name": "hours_per_day", "in": "query", "required": true, "schema": { "type": "number" }, "example": 5 }, { "name": "days_per_month", "in": "query", "required": false, "schema": { "type": "number" }, "example": 30 }, { "name": "rate_per_kwh", "in": "query", "required": true, "schema": { "type": "number" }, "example": 0.18 }, { "name": "quantity", "in": "query", "required": false, "schema": { "type": "number" }, "example": 1 }, { "name": "duty_cycle_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 100 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/ev-vs-gas": { "get": { "operationId": "ev_vs_gas", "summary": "EV vs Gas Cost Calculator", "description": "Compare EV charging cost with gasoline cost per mile, per month, and per year using your electricity rate, EV efficiency, MPG, and gas price. Human source: https://tannerd.net/tools/ev-vs-gas-cost-calculator/", "parameters": [ { "name": "miles_per_month", "in": "query", "required": true, "schema": { "type": "number" }, "example": 1000 }, { "name": "ev_kwh_per_100_miles", "in": "query", "required": true, "schema": { "type": "number" }, "example": 30 }, { "name": "electricity_rate", "in": "query", "required": true, "schema": { "type": "number" }, "example": 0.18 }, { "name": "charging_efficiency_pct", "in": "query", "required": false, "schema": { "type": "number" }, "example": 90 }, { "name": "gas_mpg", "in": "query", "required": true, "schema": { "type": "number" }, "example": 30 }, { "name": "gas_price", "in": "query", "required": true, "schema": { "type": "number" }, "example": 3.5 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/break-even-point": { "get": { "operationId": "break_even_point", "summary": "Break-even Point Calculator", "description": "Calculate break-even units and break-even revenue from fixed costs, selling price, and variable cost per unit. Human source: https://tannerd.net/tools/break-even-point-calculator/", "parameters": [ { "name": "fixed_costs", "in": "query", "required": true, "schema": { "type": "number" }, "example": 5000 }, { "name": "price_per_unit", "in": "query", "required": true, "schema": { "type": "number" }, "example": 80 }, { "name": "variable_cost_per_unit", "in": "query", "required": true, "schema": { "type": "number" }, "example": 50 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/marketing-metrics": { "get": { "operationId": "marketing_metrics", "summary": "Marketing Metrics Calculator \u2013 CPC, CPM, CPA, ROAS & CTR", "description": "Calculate CPC, CPM, CPA, CTR, conversion rate, and ROAS from ad spend, impressions, clicks, conversions, and revenue. Human source: https://tannerd.net/tools/marketing-metrics-calculator/", "parameters": [ { "name": "spend", "in": "query", "required": true, "schema": { "type": "number" }, "example": 1500 }, { "name": "impressions", "in": "query", "required": false, "schema": { "type": "number" }, "example": 100000 }, { "name": "clicks", "in": "query", "required": false, "schema": { "type": "number" }, "example": 2500 }, { "name": "conversions", "in": "query", "required": false, "schema": { "type": "number" }, "example": 100 }, { "name": "revenue", "in": "query", "required": false, "schema": { "type": "number" }, "example": 5000 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/customer-ltv-cac": { "get": { "operationId": "customer_ltv_cac", "summary": "Customer LTV:CAC Calculator", "description": "Estimate customer lifetime revenue, gross-profit LTV, and LTV:CAC ratio from average order value, purchase frequency, customer lifespan, gross margin, and CAC. Human source: https://tannerd.net/tools/customer-ltv-cac-calculator/", "parameters": [ { "name": "average_order_value", "in": "query", "required": true, "schema": { "type": "number" }, "example": 80 }, { "name": "purchases_per_year", "in": "query", "required": true, "schema": { "type": "number" }, "example": 4 }, { "name": "customer_lifespan_years", "in": "query", "required": true, "schema": { "type": "number" }, "example": 3 }, { "name": "gross_margin_pct", "in": "query", "required": true, "schema": { "type": "number" }, "example": 50 }, { "name": "cac", "in": "query", "required": true, "schema": { "type": "number" }, "example": 75 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/cash-runway": { "get": { "operationId": "cash_runway", "summary": "Cash Runway & Burn Rate Calculator", "description": "Calculate monthly net burn and cash runway from current cash, monthly revenue, and monthly expenses. Human source: https://tannerd.net/tools/cash-runway-calculator/", "parameters": [ { "name": "cash_balance", "in": "query", "required": true, "schema": { "type": "number" }, "example": 50000 }, { "name": "monthly_revenue", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10000 }, { "name": "monthly_expenses", "in": "query", "required": true, "schema": { "type": "number" }, "example": 15000 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/freelance-rate": { "get": { "operationId": "freelance_rate", "summary": "Freelance Hourly Rate Calculator", "description": "Calculate the minimum billable hourly rate needed to cover a target annual income and business overhead from realistic billable weeks and hours. Human source: https://tannerd.net/tools/freelance-rate-calculator/", "parameters": [ { "name": "target_income", "in": "query", "required": true, "schema": { "type": "number" }, "example": 70000 }, { "name": "annual_overhead", "in": "query", "required": false, "schema": { "type": "number" }, "example": 10000 }, { "name": "billable_weeks", "in": "query", "required": true, "schema": { "type": "number" }, "example": 46 }, { "name": "billable_hours_per_week", "in": "query", "required": true, "schema": { "type": "number" }, "example": 25 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/unit-price-compare": { "get": { "operationId": "unit_price_compare", "summary": "Unit Price Comparison Calculator", "description": "Compare two package prices by unit and see which option is cheaper plus the percentage difference. Human source: https://tannerd.net/tools/unit-price-comparison-calculator/", "parameters": [ { "name": "price_a", "in": "query", "required": true, "schema": { "type": "number" }, "example": 12.99 }, { "name": "quantity_a", "in": "query", "required": true, "schema": { "type": "number" }, "example": 16 }, { "name": "price_b", "in": "query", "required": true, "schema": { "type": "number" }, "example": 17.49 }, { "name": "quantity_b", "in": "query", "required": true, "schema": { "type": "number" }, "example": 24 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/dimensional-weight": { "get": { "operationId": "dimensional_weight", "summary": "Dimensional Weight Calculator", "description": "Calculate dimensional shipping weight from package dimensions and a user-entered DIM divisor, then compare it with actual weight. Human source: https://tannerd.net/tools/dimensional-weight-calculator/", "parameters": [ { "name": "length_inches", "in": "query", "required": true, "schema": { "type": "number" }, "example": 18 }, { "name": "width_inches", "in": "query", "required": true, "schema": { "type": "number" }, "example": 12 }, { "name": "height_inches", "in": "query", "required": true, "schema": { "type": "number" }, "example": 10 }, { "name": "dim_divisor", "in": "query", "required": true, "schema": { "type": "number" }, "example": 139 }, { "name": "actual_weight", "in": "query", "required": false, "schema": { "type": "number" }, "example": 8 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/date-difference": { "get": { "operationId": "date_difference", "summary": "Days Between Dates Calculator", "description": "Exact calendar-day difference between two ISO dates. Human source: https://tannerd.net/tools/date-difference-calculator/", "parameters": [ { "name": "start_date", "in": "query", "required": true, "schema": { "type": "string", "format": "date" }, "example": "2026-09-01" }, { "name": "end_date", "in": "query", "required": true, "schema": { "type": "string", "format": "date" }, "example": "2026-09-30" } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/percentage-change": { "get": { "operationId": "percentage_change", "summary": "Percentage Change Calculator", "description": "Percentage increase or decrease between an original value and a new value. Human source: https://tannerd.net/tools/percentage-change-calculator/", "parameters": [ { "name": "original", "in": "query", "required": true, "schema": { "type": "number" }, "example": 100 }, { "name": "new_value", "in": "query", "required": true, "schema": { "type": "number" }, "example": 125 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/api/v1/salary-to-hourly": { "get": { "operationId": "salary_to_hourly", "summary": "Salary to Hourly Calculator", "description": "Convert annual salary to equivalent hourly, weekly, and monthly amounts from weekly hours. Human source: https://tannerd.net/tools/salary-to-hourly-calculator/", "parameters": [ { "name": "annual_salary", "in": "query", "required": true, "schema": { "type": "number" }, "example": 60000 }, { "name": "hours_per_week", "in": "query", "required": false, "schema": { "type": "number" }, "example": 40 } ], "responses": { "200": { "description": "Calculation result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CalculatorResponse" } } } }, "400": { "description": "Invalid input", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } } }, "components": { "schemas": { "CalculatorResponse": { "type": "object", "required": [ "ok", "calculator", "inputs", "result", "formula", "source", "reviewed" ], "properties": { "ok": { "type": "boolean" }, "calculator": { "type": "string" }, "inputs": { "type": "object" }, "result": { "type": "object" }, "formula": { "type": "string" }, "source": { "type": "string", "format": "uri" }, "reviewed": { "type": "string", "format": "date" } } }, "ErrorResponse": { "type": "object", "properties": { "ok": { "type": "boolean", "const": false }, "error": { "type": "string" }, "parameter": { "type": [ "string", "null" ] }, "docs": { "type": "string", "format": "uri" } } } } } }