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Date Calculator

Find the time between two dates, or add and subtract days, weeks, months or years.

Runs in your browserNo sign-up required

Two Date Problems, One Tool

“Date calculator” usually means one of two things: how much time separates two specific dates, or where you land after moving a fixed number of days forward or backward from a starting point. Both come up constantly — deadlines, notice periods, ages, countdowns — and both are easy to get subtly wrong doing the math by hand, especially once a month or leap year boundary is involved. This calculator handles both, with a full breakdown (total days, business days, and a years/months/days split) rather than just a single number.

Where This Actually Gets Used

  1. 1Contract and project deadlinesWorking out exactly how many business days remain before a delivery deadline, excluding weekends, is the kind of calculation people get wrong by hand more often than not — especially across a month boundary.
  2. 2Age and milestone calculationsFinding someone's exact age in years, months, and days, or how many days remain until a specific milestone date, is more precise with a calculator than counting on a calendar.
  3. 3Due dates and countdownsAdding a fixed number of days to a start date — a 90-day notice period, a 45-day payment term, a 14-day return window — is a common calculation for anything with a countdown attached to it.
  4. 4Legal and financial notice periodsMany notice periods and statutory deadlines are specified in calendar days, not business days, and getting the count off by even one day can matter — this calculator shows both counts side by side to avoid that ambiguity.

How to Use This Calculator

  1. 1Choose a mode"Days between two dates" or "add/subtract days from a date."
  2. 2Pick your date(s)Use the date pickers to select a start date and, if relevant, an end date.
  3. 3For add/subtract, enter a number of daysPositive to move forward, negative to move backward — the resulting date updates instantly.
  4. 4Read the full breakdownTotal days, business days, and a years/months/days split are all shown at once.

Frequently Asked Questions

How many business days are between two dates?

The "Weekdays" figure counts Monday to Friday. To also skip public holidays (US, UK or India lists, or your own dates), use the Business Days Calculator linked under the results.

How do I add or subtract days from a date?

Switch to "Add or subtract", pick the start date, choose Add or Subtract, and enter an amount in days, weeks, months or years. The result shows the full date with its weekday and how far it is from today.

Does this calculator include both the start and end date when counting?

By default it counts the difference between the dates, so 1 June to 3 June is 2 days (like 2 hotel nights). Tick "Include the end date" to count both days — 1 to 3 June becomes 3 days (like a 3-day trip).

What's the difference between the "years/months/days" breakdown and "total days"?

Total days is a single number — the full span converted entirely into days. The years/months/days breakdown expresses the same span the way a calendar would, which is more intuitive for describing someone's age or a long duration.

What happens when I add a month to 31 January?

You get the last day of February (28th, or 29th in a leap year), since 31 February doesn't exist. Month and year maths always keeps the same day of the month when it can.

Does this calculator account for leap years?

Yes — all calculations are done using actual calendar dates, so leap years are automatically accounted for in every result.

Is this date calculator free to use?

Yes, completely free, with no sign-up, and it runs entirely in your browser.