Add or subtract days, weeks, months or years from any date.
Calculated instantly in your browser.
How do you add or subtract days from a date?
A date calculator adds or subtracts a span of days, weeks, months or years from a starting date and shows the resulting date and weekday. Month and year steps account for different month lengths, so adding one month to 31 January lands on the correct end-of-month date. For example, 90 days after 21 June 2026 is 19 September 2026.
Understanding your result
Month and year steps account for different month lengths, so adding one month to 31 January lands on the correct end-of-month date.
Assumptions and limitations
The calculator shifts one calendar date by a fixed span and returns the resulting date and weekday. It does not skip weekends or public holidays, so it is not a working-days scheduler. It also handles a single date rather than a range, and does not add clock times such as hours or minutes.
Worked example
90 days after 21 June 2026 is 19 September 2026.
How to use this tool
- Pick a start date.
- Choose add or subtract, an amount and a unit.
- Press Calculate.
About the Date Calculator (Add / Subtract)
The Date Calculator adds or subtracts a span of days, weeks, months or years from a starting date and shows the resulting date and weekday.
Who should use this tool
Useful for anyone projecting a date forward or back: staff calculating deadlines, warranty or return windows, renewal and expiry dates, or due dates; planners scheduling ahead by a set period; and anyone who needs the resulting weekday too. If you have a start date and a number of days, weeks, months or years, this handles it.
Benefits
- Adds or subtracts days, weeks, months or years in one step
- Lands correctly on month ends despite varying month lengths
- Shows the resulting weekday, not just the date
- Instant and private, running entirely in your browser
Practical use cases
- Finding a deadline a set number of days ahead
- Working out a warranty or return expiry date
- Scheduling a renewal months in advance
- Checking which weekday a future date falls on
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Frequently asked questions
Does it handle leap years?
Yes. Adding days, months or years uses the calendar, so leap years and varying month lengths are handled automatically.
What happens when I add a month to the 31st?
Month steps respect the differing lengths of each month, so adding one month to 31 January lands on the correct end-of-month date rather than overflowing into the next month. This keeps monthly renewals and recurring dates predictable even when the target month has fewer days than the start.
Can it skip weekends and give me a business date?
No. The calculator counts plain calendar days, so it includes weekends and public holidays in the span. It cannot produce a business-day result or knowledge of regional holidays. For working-day scheduling you would need a tool built specifically to exclude non-working days.