About the Add Days to Date
Find the date a number of days, weeks, months or years before or after any date, such as deadlines, due dates or anniversaries, with correct month-end and leap-year handling.
Key features
- Add or subtract days, weeks, months and years
- Combine units (e.g. 1 year, 2 months and 10 days)
- Correct month-end handling (31 Jan + 1 month = 28/29 Feb)
- Weekday of the resulting date
- ISO date output
- Handles leap years
Find a date in the future or past
Deadlines, notice periods, warranties, medication schedules, subscription renewals and contract terms are often defined as "X days from" a date. Pick a start date, add or subtract a period, and see the exact resulting date and weekday.
Examples from 20 October 2026
| Period | Resulting date |
|---|---|
| + 7 days | Tue, 27 Oct 2026 |
| + 30 days | Thu, 19 Nov 2026 |
| + 90 days | Mon, 18 Jan 2027 |
| + 6 months | Tue, 20 Apr 2027 |
| + 1 year | Wed, 20 Oct 2027 |
| − 100 days | Sun, 12 Jul 2026 |
Days vs months
"30 days" and "1 month" are not the same:
- 31 Jan + 30 days = 2 Mar (in 2026)
- 31 Jan + 1 month = 28 Feb (in 2026)
Check which your contract or policy uses.
Common periods
| Use | Typical period |
|---|---|
| Return window | 14, 30 or 60 days |
| Notice period | 2 weeks to 3 months |
| Invoice terms | Net 30, Net 60 |
| Visa stays | 90 days in 180 |
| Warranties | 1–2 years |
Related calculators
Count business days with the Working Days Calculator, or measure the gap between two dates with the Date Difference Calculator.
How to use the Add Days to Date
- Enter your numbers in the fields above. Units and options can be changed at any time.
- The result updates instantly as you type; there's no calculate button to press.
- Check the breakdown under the main result for the details behind the number.
- Adjust the inputs to compare scenarios, for example a different rate or term.