Does “days between” count both ends?

This tool counts calendar-day intervals — the difference between two dates. For example Oct 1 to Oct 2 is 1 day; if you want “inclusive of both ends”, add 1 to the result.

Does add/subtract respect month lengths?

Yes. It uses the real calendar, so Jan 31 plus 1 day becomes Feb 1, and leap-year February rolls over correctly.

No. All calculation happens locally in your browser; dates are never sent to a server.

Date Calculator Util123 · Days between / add & subtract

Date Calculator

How many days between two dates? What date is 30 days from now? Common but easy to miscount — let this handle it.

Difference between two dates

Start date

End date

Add / subtract days

Start date

Days to add (negative to subtract)

FAQ

Does “days between” count both ends?: This tool counts calendar-day intervals — the difference between two dates. For example Oct 1 to Oct 2 is 1 day; if you want “inclusive of both ends”, add 1 to the result.
Does add/subtract respect month lengths?: Yes. It uses the real calendar, so Jan 31 plus 1 day becomes Feb 1, and leap-year February rolls over correctly.
Is my date uploaded?: No. All calculation happens locally in your browser; dates are never sent to a server.