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Date Calculator

Add or subtract time from a date to find the resulting date.

Result date

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What this calculator does

This date calculator adds or subtracts any number of days, weeks, months, or years from a starting date. It's the tool to reach for whenever you need to calculate a future or past date without manually counting on a calendar.

Worked example

Starting from May 10, 2026 and adding 90 days lands onAugust 8, 2026, a Saturday.

Common mistakes

  • Treating a month as exactly 30 days. Adding "1 month" and adding "30 days" often produce different results, since real months range from 28 to 31 days.
  • Month-end overflow. Adding a month to January 31 lands on the last day of February, not March 3, since February doesn't have 31 days.
  • Sign confusion when subtracting. Double-check whether you want to go backward from today or forward — the operation toggle controls the direction.

Frequently asked questions

How does adding months to a date work at month-end?+

If the resulting month doesn't have the same day number — for example, adding 1 month to January 31 — the date rolls to the last day of that month (February 28 or 29), since February 31 doesn't exist.

Can I subtract time from a date instead of adding?+

Yes — switch the operation to "subtract" to go backward from your starting date by the chosen number of days, weeks, months, or years.

What day of the week does the result fall on?+

The result includes the full weekday name so you can immediately see whether it lands on a weekday or weekend.

Does this account for time zones?+

No — this calculator works with calendar dates only, not specific times or time zones, so results are the same regardless of where you are.

Related calculators

Leap Year CheckerCheck instantly whether a year is a leap year. Days Between Two Dates CalculatorFind the exact number of days between two dates. Add or Subtract Days CalculatorAdd or subtract a number of days from a date. Date Duration CalculatorFind the duration between two dates in years, months, and days.