Days Between Dates Calculator

Find the exact number of calendar days between a start date and an end date.

Start dateEnd date

Enter your numbers and calculate.

Examples

Example	Result
August 31 → September 30	30 days
January 1 → January 8	7 days

Frequently asked questions

Does this count the start date?

It calculates elapsed calendar-day difference, so January 1 to January 2 is one day.

Can the end date be earlier?

Yes. The tool reports the absolute number of days and indicates the ordering.

Does daylight saving time affect it?

Using calendar dates at local midnight avoids most everyday time-of-day concerns for this simple calculation.

Public API & AI agent access

Yes — Days Between Dates Calculator is callable programmatically through /api/v1/date-difference, the public calculator API, MCP, A2A and WebMCP. Structured results include a human-facing citation URL.

Formula provenance

API identifier: date-difference · Formula version: tncalc.date-difference.1.0.0 · Engine release: 6.6.1. Build provenance · Public validation · Release history.