Find the date a given number of days, weeks or months from a start date — forwards or backwards, calendar days or working days.
Pick a starting date, say how far to move and in which direction, and get the exact date — including which day of the week it lands on.
Resulting date
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How Does It Work?
Choose the start dateIt defaults to today, so "90 days from today" takes one edit.
Set the amount and unitDays, working days, weeks, months or years. Months and years keep the same day number where possible.
Pick a directionAdd to look forward, subtract to look back at when something must have started.
What Is It Used For?
Deadlines are usually expressed as a period rather than a date: 30 days to pay, 14 days to return, 90 days probation. This tool converts that period into the actual calendar date, and tells you the weekday so you can spot a deadline falling on a Sunday.
Finding the due date of a 30-day invoice.
Working out the last day of a 14-day return window.
Setting the end of a probation or notice period.
Counting forward in working days for a service level agreement.
Looking backwards to find when a countdown must have started.
Examples
Start
Move
Result
1 Jan 2026
+30 calendar days
31 January 2026
1 Jan 2026
+30 working days
12 February 2026
31 Jan 2026
+1 month
28 February 2026
15 Mar 2026
−90 days
15 December 2025
Frequently Asked Questions
What date will it be in 30 days?
Leave the start date as today, enter 30, keep the unit on calendar days and the answer appears with its weekday.
How are months added?
The day number is kept where possible. Adding one month to 31 January gives 28 February (or 29 in a leap year), because February has no 31st. This matches how contracts are normally read.
What counts as a working day here?
Monday to Friday. Public holidays are not deducted — if you need those, count the range in the Working Days Calculator instead.
Can I go backwards?
Yes. Switch the direction to "Before (subtract)" and the calculator counts back from your start date.
Does it handle leap years?
Yes. Day arithmetic uses real calendar dates, so 29 February is included whenever it falls inside the range.
What does "30 days to pay" actually mean?
Usually 30 calendar days counted from the day after the invoice date, unless the terms say working days. Set the invoice date as the start, add 30 calendar days, and check whether the result lands on a weekend when the payment will not clear.
Is the starting day counted?
No. Adding 30 days to 1 January gives 31 January, counting from the day after the start. Some contracts count the first day as well, which shifts everything by one, so read the wording before relying on a date.
Free. No registration. This tool runs entirely in your browser, so the data you enter stays on your device.