How do I add days to a date?

Pick the start date, leave the operation on 'Add', and enter the number of days (and optionally weeks, months, years). The result date updates instantly.

How are months and years added?

Years and months are applied first as calendar units, clamping to the last valid day (Jan 31 + 1 month = Feb 28/29). Weeks and days are then added as exact 24-hour days.

What is the total day offset?

It is the net number of calendar days between the start date and the result — positive when adding, negative when subtracting.

Date Add / Subtract Calculator

Free add/subtract date calculator. Pick a start date, choose to add or subtract, and enter years, months, weeks and days to get the resulting date and the total day offset.

Add or subtract years, months, weeks and days from any date.

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