Date Calculator
Date calculator online. Add or subtract days, weeks, or months from a date. Free add days to date tool.
2026-09-05T22:01:30.492Z
Unix 1788645690 · Sat, 05 Sep 2026 22:01:30 GMT
Features
- Date calculator online: add or subtract days, weeks, months, or years
- Start from now, a Unix timestamp, or an ISO date
- UTC calendar math for months and years
- See the result in ISO and Unix
- Free add-days-to-date tool. No server
Common Use Cases
- Compute trial-end = now + 14 days
- Find 90 days after a contract start
- Subtract 3 hours from an incident timestamp
- Build a reminder instant
- Check month-end clamping (Jan 31 plus one month)
Calendar add is not duration multiply
Adding one month to 31 January is not “plus 30 days”. Engines clamp to a valid civil date. We use UTC getters/setters so your OS timezone does not shift the day while you add hours.
Examples
Valid - Plus 7 days
now + 7 daysFrequently Asked Questions
How do I add days to a date?
Paste a start date (or use now), enter how many days, pick “days”, and read the result. Same idea for weeks and months.
Is this business days?
No. Weekends and holidays are not skipped. Use a business-day library for that.
Tips
- Add months in UTC if you care about not slipping a local DST hour.
- For SLAs, prefer hours and days over months.