Add or Subtract Days from a Date
Add or subtract days, weeks, months or years from any date and get the result instantly.
Uses the Days field only — weeks, months and years are ignored.
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- ISO format
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- Day of week
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- Calendar days
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- Weekend days skipped
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- Day of year
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- ISO week
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How it works
Pick a start date, choose whether to add or subtract, and type how many days (or weeks, months and years) you want to shift it by — the new date appears instantly, together with the day of the week, the ISO format, the day of the year and the ISO week number. Month and year steps use calendar arithmetic and clamp to the end of a shorter month, so 31 January plus one month gives 28 February (29 February in a leap year), exactly the way contracts and deadlines are normally read.
Tick Count business days only to skip Saturdays and Sundays — handy for invoice terms, notice periods and court or shipping deadlines that are counted in working days. All the maths runs in your browser in UTC, so daylight-saving changes can never shift the answer by a day, and the dates you enter are never uploaded, logged or tracked.
Frequently asked questions
How do I add 30 days to a date?
Pick your start date, leave the operation on Add, and type 30 in the Days field. The new date appears instantly, along with the day of the week, the ISO date (YYYY-MM-DD), the day of the year and the ISO week number. You can copy the whole result or download it as a text file.
What date is 90 days from today?
Press the Today button to load the current date, keep the operation on Add and enter 90 in the Days field. The tool counts 90 calendar days forward, including weekends and holidays, and shows the exact resulting date and weekday. Tick "Count business days only" if your 90 days should skip Saturdays and Sundays instead.
How does the tool handle business days and months of different lengths?
With "Count business days only" ticked, Saturdays and Sundays are skipped and the tool reports how many weekend days it stepped over; public holidays vary by country, so they are not applied. Month and year steps use calendar arithmetic and clamp to the last day of a shorter month, so 31 January plus one month gives 28 February (29 February in a leap year).