Date Calculator
Add or subtract days from a date.
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📝 About Date Calculator
The Date Calculator adds or subtracts a number of days from any base date and shows the resulting date together with its day of the week. Choose a base date, enter how many days to move, and press Add or Subtract.
Typical uses include finding a due date that falls 30 days after an invoice, checking when a 90-day trial or warranty ends, working out a refund or return deadline, planning a schedule that starts “two weeks before” an event, or calculating the date of a 100th or 1,000th day anniversary.
The tool works with calendar days, not business days, and it automatically handles different month lengths and leap years, so adding 1 day to February 28 gives February 29 in a leap year and March 1 otherwise. All calculations are done in UTC, which prevents daylight saving time from shifting the result. Tip: when a deadline is defined in business days rather than calendar days, use the Workday Calculator to check how many weekdays fall within the period.
📘 How to use
- 1
Pick a base date
Choose the starting date; it defaults to today.
- 2
Enter the number of days
Type how many calendar days you want to move forward or back.
- 3
Add or subtract
Press Add or Subtract to see the resulting date and its weekday.
❓ FAQ
Does it skip weekends or holidays?
No. It counts every calendar day, including weekends and holidays. Use the Workday Calculator if you need to count weekdays only.
Are leap years taken into account?
Yes. Month lengths and February 29 in leap years are handled automatically.
Is the base date counted as day 1?
No. Adding 1 day to today returns tomorrow. If your rule counts the base date as day 1, enter one day fewer.