1. Choose a start date
Today is filled in for you. Change it to any date, past or future.
Add or Subtract Days
Add or subtract days, business days, weeks, months or years from any date and see the exact result, including the day of the week.
- Free, no sign-up
- Instant results
- Nothing is stored
Result
Saturday, 7 November 2026
30 calendar days after- ISO date
- 2026-11-07
- Week number
- Week 45 of 2026
- Day of the year
- Day 311 of 365
The start date is day zero and is not counted.
How it works
Find any date in three steps
2. Add or subtract
Enter an amount and pick days, business days, weeks, months or years. Quick buttons cover the common ones.
3. Get the date
See the exact date and weekday, its week number, and save it to your calendar.
Examples
How each unit behaves
Every example starts from Saturday 31 January 2026.
| Add | Rule | Result |
|---|---|---|
| 30 days | Every calendar day counts | Mon 2 Mar 2026 |
| 10 business days | Saturdays and Sundays are skipped | Fri 13 Feb 2026 |
| 2 weeks | Exactly 14 days | Sat 14 Feb 2026 |
| 1 month | Same day next month, or its last day | Sat 28 Feb 2026 |
| 1 year | Same date next year | Sun 31 Jan 2027 |
FAQ
Common questions
Is the start date counted?
No. Adding 1 day to 10 March gives 11 March. The start date is day zero, which matches how deadlines like "within 30 days" are normally worked out.
What happens when I add a month to 31 January?
February has no 31st, so the result moves to the last day of February: 28 February, or 29 February in a leap year. The same rule applies to any month that is shorter than the start month.
How are business days added?
Business days skip Saturdays and Sundays. Adding 10 business days to Friday 9 January 2026 gives Friday 23 January 2026. Public holidays are not skipped; use the Business Days Calculator if you need them.
Can I count backwards?
Yes. Choose "Subtract" to find the date a number of days, weeks, months or years before your start date.
What is the week number shown?
It is the ISO 8601 week number, where weeks start on Monday and week 1 is the week that contains the first Thursday of the year.
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