Date calculator
Three date sums in one place: move a date forward or back, count the days between two dates, or count working days.
Runs in your browser. What you type is not sent to a server.
Which tab to use
Add or subtract answers "what date is 90 days from today?" or "what was the date 6 months ago?". Years and months are applied first, then weeks and days, and a month step that lands past the end of a shorter month stops on its last day. Between two dates answers "how many days until…" or "how long ago was…", in days, weeks and years, months and days. Business days counts only Monday to Friday and takes out the public holidays of the country you pick. It opens with your country when your browser reports it.
Each tab has a link to its full tool under the result, with your dates already filled in. The full tools do more: the business days calculator has holidays for more than 200 countries, your own days off and an Excel formula, and days between dates keeps your recent results.
Examples from November 5, 2026
These are the answers each tab gives, counted from Thursday, November 5, 2026.
| Tab | You enter | Answer |
|---|---|---|
| Add or subtract | Add 90 days | Wed, Feb 3, 2027 |
| Add or subtract | Add 6 months | Wed, May 5, 2027 (181 days later) |
| Add or subtract | Add 1 year and 2 weeks | Fri, Nov 19, 2027 |
| Add or subtract | Subtract 30 days | Tue, Oct 6, 2026 |
| Between two dates | To Dec 25, 2026 | 50 days: 1 month and 20 days, 7 weeks and 1 day |
| Between two dates | To Nov 5, 2027 | 365 days: exactly 1 year |
| Business days | To Dec 25, 2026, both dates counted | 34 with US holidays, 36 with UK holidays, 37 with none |
| Business days | To Nov 5, 2027, both dates counted | 251 with US holidays, 254 with UK holidays, 262 with none |
The business day counts differ because of which holidays fall on weekdays in between. Up to Christmas, the US list takes out Veterans Day (November 11), Thanksgiving (November 26) and Christmas Day, while England and Wales only lose Christmas Day; Boxing Day 2026 is a Saturday, and its substitute Monday comes after the 25th. Note that 6 months and 180 days are not the same: 6 months from November 5 is May 5, one day after 180 days.
Counting the first and last day
The tabs count the way most people mean each question. Adding days starts from tomorrow, so 1 day from Thursday is Friday. Between two dates gives the gap, so Monday to the next Monday is 7 days; tick "Include the end date" when you are counting days of a stay or an event. Business days count both the start and the end by default, so Monday to Friday of one week is 5; untick either box to leave it out, which is how many "within 10 business days" rules are read.
Questions
Can I share or bookmark a calculation?
Yes. Press Copy link. The link opens this page on the same tab with the same dates and numbers, so whoever opens it sees the same answer.
Why do two date calculators give different answers?
Usually because one counts the first or last day and the other doesn't, or because one counts business days with holidays and the other without. Check those two settings first. For month steps, some calculators roll January 31 plus one month over into March; this one stops at the end of February.
Does it work for dates in the past?
Yes. Choose Subtract to go back from a date, or put the earlier date second in Between two dates; the answer is the same number of days and says the end date is earlier. US federal holidays and England and Wales bank holidays are worked out from their official rules for past and future years.