Add or Subtract Days Calculator
Add or subtract years, months, weeks or days from a date, or count business days with your weekend and days off — shown as ISO, spelled-out date and weekday.
Use a negative number to go backwards. Fill in as many as you need — they are all applied at once.
2026-11-10
November 10, 2026
Tuesday
7 calendar days later (1 week)
All the units at once
Pick a start date and fill in as many of years, months, weeks and days as you need — they are applied together, so “+1 year 2 months 10 days” is one answer rather than three trips through the tool. Any of them can be negative to go backwards, and a box left empty simply means none of that unit. The result comes back three ways: the ISO date for pasting into something, the same date written out for reading, and the weekday it lands on. Below those, the shift is also counted in calendar days — a month from 31 January 2024 is “29 calendar days later (4 weeks 1 day)” — so a span given in months reads as a number of days. Under the boxes, the “Common shifts” buttons fill them in one press — a month or a quarter counted in days, half a year, a year, or a fortnight back — and the button that matches the boxes stays marked. To count the time between two dates instead, use the Date Difference Calculator.
Business days, on the same screen
Switch to business days and the count skips non-working days instead of counting calendar days. What counts as the weekend is yours to set — Saturday and Sunday, Friday and Saturday, Sunday alone, or none — the United States federal holidays can be ticked on rather than typed, and the days your own office is closed go in one per line, each with a name after the date if you want one. The answer then says how it got there: the calendar days it spanned, the weekend days it skipped and the days off it skipped. The start date itself is never counted, so one working day from a Friday is the following Monday. When the start date is itself a day off, "If the start date is a day off" chooses whether to count from it anyway, as by default, or to start from the next or the previous working day.
Months that do not have a 31st
Adding a month to 31 January gives the last day of February, not the 2nd or 3rd of March: a month after the 31st means the end of the next month, and that is what a spreadsheet’s EDATE function returns. The calendar units are applied before the day count for the same reason — so “one month and one day after 31 January” is 1 March, and does not depend on which unit happened to be handled first.
Frequently asked questions
Can I add years, months and days at the same time?
Yes. Fill in as many of the four boxes as you need and they are applied in one go. The order is fixed: years and months first, then weeks and days, which is the usual order in spreadsheets and date libraries and what makes the answer independent of how you typed it.
How do I add working days rather than calendar days?
Switch to the business-days mode. Set which days are your weekend, type in any days the office is closed, and the count steps over all of them. Use a negative number to count backwards to a date that is N working days before.
What happens when the target month is shorter?
The date is clamped to the last day of that month. One month after 31 January is 28 or 29 February depending on the year, and one year after 29 February is 28 February — never the 1st or 2nd of the following month.
Are public holidays included?
The United States federal list can be ticked on; everything else is yours to type in, either a bare date or a date with a name after it. Only a list that can be worked out from a rule is offered, and the US one is — every date comes from the statute rather than a stored table. Anything else differs by country, by region and by year, and several holidays move with the lunar calendar. A built-in list that is quietly out of date would be worse than none, because nobody checks it.
What if my weekend is not Saturday and Sunday?
Tick the days you work. The weekend menu still fills them in for the common patterns, and shows “Your own” when your days match none of them.
What if the start date is itself a day off?
Choose in "If the start date is a day off". "Count from it anyway" is the default; "Start from the next working day" and "Start from the previous working day" step over weekends and listed days off alike, and the days they step over are counted in the line that says what was skipped.
Are there shortcuts for the usual spans?
Yes. Under the four boxes, “Common shifts” fills them in one press — a month or a quarter counted in days, half a year, a year, or two weeks back — and clears the others, so the boxes show exactly what was added. The button that matches the boxes stays pressed, and any box can still be changed afterwards.