Date calculator
Three date sums in one place: move a date forward or back, count the days between two dates, or count working days.
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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.
The Between two dates and Business days tabs link to their full tools 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 (379 days later) |
| 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: 1 year, 52 weeks and 1 day |
| 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.
Month ends, leap years and weekends
When you add months, the calculator keeps the same day of the month. If that day doesn't exist, it stops on the last day of the month instead of rolling over: January 31 plus one month is February 28, or February 29 in a leap year. These are the cases that most often surprise people, worked out by the same calculator:
| Start | Add | Result | What to know |
|---|---|---|---|
| Sat, Jan 31, 2026 | 1 month | Sat, Feb 28, 2026 | stops on the last day of February, and falls on a Saturday |
| Tue, Mar 31, 2026 | 1 month | Thu, Apr 30, 2026 | stops on the last day of April |
| Mon, Aug 31, 2026 | 6 months | Sun, Feb 28, 2027 | stops on the last day of February, and falls on a Sunday |
| Mon, Jan 31, 2028 | 1 month | Tue, Feb 29, 2028 | stops on the last day of February |
| Tue, Feb 29, 2028 | 1 year | Wed, Feb 28, 2029 | stops on the last day of February |
| Thu, Nov 5, 2026 | 30 days | Sat, Dec 5, 2026 | falls on a Saturday |
| Thu, Nov 5, 2026 | 6 months | Wed, May 5, 2027 | 181 calendar days later |
| Thu, Nov 5, 2026 | 180 days | Tue, May 4, 2027 | 180 calendar days later |
Going one month at a time does not undo itself. January 31 plus one month is February 28, but February 28 plus one month is March 28, so adding "1 month" twice is not always the same as adding "2 months" once. When a payment or renewal is due on the last day of each month, work from the original date each time rather than from last month's result. Weeks are always seven days, so 6 weeks from a Wednesday is also a Wednesday.
Where adding days comes up
- Deadlines and notice periods: "within 30 days of the invoice", "60 days' notice". If the deadline counts working days, use the Business days tab.
- Returns and warranties: a 90-day return window or a 1-year warranty from the purchase date.
- Health: a follow-up in 6 weeks, a course of medicine that lasts 14 days.
- Travel and visas: when a 90- or 180-day period ends. Visa rules often count the arrival day too, so check the exact wording.
- Milestones: 100 days since a launch, 1,000 days since you met, 10,000 days old.
Questions
What is the date 90 days from today?
Ninety days from today is a date about three months away. Use Add or subtract above with 90 in the days box to start from any other date. Ninety days is not the same as three months: it lands a day or two earlier or later depending on which months are in between.
What is the date 6 months from today?
Six months from today is the same day of the month, six months on. If that month is shorter, the result is its last day, so six months from August 31 is the end of February.
How do I count the days between two dates?
Choose Between two dates and pick both dates. The answer is the number of days from the first to the second, not counting the first day, which is the usual way to count a gap. Tick "Include the end date" if you are counting the days of a stay or an event, where both the first and the last day count.
How many weeks until a date?
Between two dates shows the gap in weeks and days as well as in days. For example, November 5 to December 25, 2026 is 50 days, or 7 weeks and 1 day.
What if the result falls on a weekend?
The calculator still gives the calendar date, because that is what "30 days" means, and says that it is a Saturday or Sunday. Many deadlines that end on a weekend or holiday move to the next working day, but not all do, so check the rule you are working with. To count only working days from the start, use the Business days tab.
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.