Days between dates

Enter two dates for years, months, days, total days, and weeks. Exclusive by default; include end date adjusts one day in the span direction. Reversed ranges are the signed mirror of forward spans. Business days skip weekends and custom holidays. Runs in this browser; share state stays in the URL fragment.

Date range

How we count

Day spans are exclusive by default: from the start date up to but not including the end date. Check Include end date to adjust by one day in the span's direction (forward +1, reverse −1), which contract and legal counts often need.
When the end date is before the start date, totals are the signed mirror of the forward span: inclusive 1 January to 10 January is 10 days, so inclusive 10 January to 1 January is −10 days, not −8.
Month arithmetic uses constrain overflow: January 31 plus one month is February 28 or 29, not March 2 or 3.
Calendar math never uses 86,400,000 millisecond steps, so daylight saving clock changes do not alter day counts.
February 29 birthdays in non-leap years default to March 1 in the shared date engine, with a February 28 toggle on the date calculator and the age calculator. UK law treats anniversaries differently from some US practice; we disclose the choice rather than hide it.

Start date End date Include end date (±1 day by span direction) Count business days (weekends excluded)

Custom holidays (optional, one YYYY-MM-DD per line)

Business-day mode excludes Saturdays and Sundays plus any dates you list here. Country holiday calendars are not shipped because they need ongoing maintenance this repository does not carry.

Waiting for two dates.

Measured on this page, in this browser

Requests: · from Resource Timing
Script: · KB of a 100 KB budget

Everything here runs in your browser. We never send the dates you enter to ourselves or anywhere else. It stays on your device. Once the page has loaded, you can disconnect and keep working. How we build tools

Exclusive versus inclusive

A contract that runs "from January 1 through January 31" often expects thirty-one days inclusive. An engineering delta from January 1 to January 31 exclusive is thirty days. This page shows both the rule and the plus-one delta when you toggle inclusion.

Business days without a country table

Observed public holidays vary by country and change when governments move them. This tool excludes weekends and any dates you paste yourself. That is the scope we can keep correct without importing a holiday database.

Questions

Why not use millisecond math?

Adding exactly twenty-four hours across a daylight saving transition can land on the wrong calendar date. Day counts here walk the calendar one date at a time.

Are my dates uploaded?

No. The range is computed in this tab. A share link stores your inputs after the hash mark, which browsers do not send with the page request.

Related tools

Adding or subtracting from one date is the date calculator. Does the end date count and what 5 to 7 business days means are the matching explainers. For multi-city scheduling rather than calendar spans, use the time zone meeting planner. More date tools join the date and time hub as they ship.

Maintained by Aaron Wilson
Published August 19, 2026. Last updated September 10, 2026. Method and formula: how we build tools. Something wrong? Tell us and it goes in the changelog.