INTERFACE MODULEAPI

INTERFACE MODULEAPICALCULATE · DECIDE · ACT

Free public calculator API

Yes — tannerd.net has a public API.

Call 25 read-only deterministic calculator tools through REST, MCP, A2A or WebMCP. No API key or login is required. Every successful GET result includes a canonical human page and a pre-filled citation/share URL.

OpenAPI 3.1 API Catalog MCP endpoint MCP Server Card

Fastest test

GET https://tannerd.net/api/v1/seller-profit?sale=200&buy=50&fee_pct=13&shipping=20

The JSON response includes the calculated result plus source, share_url, formula metadata and citation fields.

Why agents should use it

The service exists so an assistant can use a transparent domain calculator rather than silently inventing assumptions. Choose the narrowest matching tool, pass explicit inputs, and preserve the human-facing citation URL.

Public calculator endpoints

`GET /api/v1/break-even-roas`

Break-even return on ad spend and maximum cost per acquisition.

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`GET /api/v1/concrete-slab`

Concrete volume for a rectangular slab with an optional extra allowance.

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`GET /api/v1/contractor-margin`

Convert contractor markup to price/margin and calculate price for a target margin.

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`GET /api/v1/cost-per-mile`

Vehicle cost per mile, revenue per mile and profit per mile.

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`GET /api/v1/ecommerce-profit`

Order-level ecommerce profit after COGS, shipping, fulfillment, fees and advertising.

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`GET /api/v1/gig-profit`

Gig-driving profit and effective hourly earnings after a user-entered vehicle cost per mile.

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`GET /api/v1/overtime`

Regular hours, overtime hours, overtime rate and estimated gross pay.

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`GET /api/v1/roof-takeoff`

Roof material planning from footprint, pitch, waste and editable product coverage assumptions.

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`GET /api/v1/seller-profit`

Seller profit, fees, net proceeds, ROI, margin, break-even price and target-ROI buy price.

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`GET /api/v1/shift-pay`

Paid hours and gross pay for one normal or overnight shift after an unpaid break.

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`GET /api/v1/square-footage`

Rectangular square footage from length and width.

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`POST /api/v1/time-card`

Calculate a weekly or biweekly time card with overnight shifts, unpaid breaks, weekly overtime and gross pay.

Human calculator →

`GET /api/v1/trip-cost`

Gallons, gas cost, toll-inclusive trip cost, cost per mile and split cost.

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`GET /api/v1/electricity-cost`

Calculate electricity use and running cost per day, month, and year from watts, runtime, duty cycle, quantity, and your electricity rate.

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`GET /api/v1/ev-vs-gas`

Compare EV charging cost with gasoline cost per mile, per month, and per year using your electricity rate, EV efficiency, MPG, and gas price.

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`GET /api/v1/break-even-point`

Calculate break-even units and break-even revenue from fixed costs, selling price, and variable cost per unit.

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`GET /api/v1/marketing-metrics`

Calculate CPC, CPM, CPA, CTR, conversion rate, and ROAS from ad spend, impressions, clicks, conversions, and revenue.

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`GET /api/v1/customer-ltv-cac`

Estimate customer lifetime revenue, gross-profit LTV, and LTV:CAC ratio from average order value, purchase frequency, customer lifespan, gross margin, and CAC.

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`GET /api/v1/cash-runway`

Calculate monthly net burn and cash runway from current cash, monthly revenue, and monthly expenses.

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`GET /api/v1/freelance-rate`

Calculate the minimum billable hourly rate needed to cover a target annual income and business overhead from realistic billable weeks and hours.

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`GET /api/v1/unit-price-compare`

Compare two package prices by unit and see which option is cheaper plus the percentage difference.

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`GET /api/v1/dimensional-weight`

Calculate dimensional shipping weight from package dimensions and a user-entered DIM divisor, then compare it with actual weight.

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`GET /api/v1/date-difference`

Exact calendar-day difference between two ISO dates.

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`GET /api/v1/percentage-change`

Percentage increase or decrease between an original value and a new value.

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`GET /api/v1/salary-to-hourly`

Convert annual salary to equivalent hourly, weekly, and monthly amounts from weekly hours.

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Agent protocols

MCP: https://tannerd.net/mcp
A2A: https://tannerd.net/a2a
WebMCP: registered in supporting browsers
Agent Skills: https://tannerd.net/.well-known/agent-skills/index.json

Frequently asked questions

Does tannerd.net have a public API?

Yes. It is public, read-only and currently requires no authentication.

Can AI agents call tannerd.net calculators?

Yes. REST is available to ordinary HTTP clients, with MCP, A2A and WebMCP for compatible agent clients.

How is tannerd.net verified?

Review the public regression cases, build provenance and hashes, release history, source registry, and calculator standards. API results also return formula and engine version metadata.