Date calculator

Add or subtract calendar days, weeks, months or years from a date.

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Date calculator processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

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Updated 2026-09-20

Using Date calculator

Days and weeks move by whole calendar days. Months and years keep the day number where possible and clamp to the last day of a shorter month. Enter a negative amount to reverse the selected operation.

A worked example

January 31, 2026 plus 1 month is February 28, 2026. Adding 2 months directly gives March 31, 2026.

Before you use the result

Gregorian calendar, years 0001–9999. Month-end clamping is not always reversible: subtracting a month from February 28 gives January 28. For working days, use the business-days calculator.

Next: Date difference calculator

Next: Business days calculator

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ToolOctopus. “Date calculator.” Updated 2026-09-20. https://tooloctopus.com/date-calculator.

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