Date Calculator

A date calculator counts the time between two dates or finds a date before or after another. This tool gives the difference in days, weeks, years-months-days and weekdays, adds or subtracts years, months, weeks and days, and calculates exact age. It handles leap years and never shifts results by a day because of your time zone.

Free, no signup. Runs entirely in your browser; files and text are not uploaded.

How to use the Date Calculator

  1. Choose Days between dates, Add or subtract, or Age calculator.
  2. Enter the start and end dates, or a start date and the amounts to add or subtract, or a date of birth.
  3. Tick Include end date if you want to count both the first and last day.
  4. Read the result and the breakdown, or copy it.

Features

  • Days between dates with years/months/days, weeks and hours
  • Weekday (Monday–Friday) count between dates
  • Add or subtract any mix of years, months, weeks and days
  • Exact age with total days and days until the next birthday
  • Leap-year aware; month-end dates handled (31 Jan + 1 month = 28/29 Feb)
  • Time-zone-safe calculations and copy button

Frequently asked questions

Does the day count include the end date?

Not by default: from 1 January to 2 January is 1 day. Tick Include end date to count both days, which adds one day.

Are leap years included?

Yes. For example, 1 January 2024 to 1 January 2025 is 366 days because 2024 has 29 February.

What happens when I add a month to 31 January?

The result moves to the last day of February (28 or 29 February), the same rule most calendar and spreadsheet software uses.

Do weekday counts exclude public holidays?

No. Weekdays are Monday to Friday; public holidays differ by country and are not removed.

Related tools

  • Time Zone Converter – Convert a date and time between world time zones with daylight saving
  • Percentage Calculator – Percent of a number, percentage change, increases, discounts and more
  • BMI Calculator – Calculate adult Body Mass Index in metric or US units
  • Loan Calculator – Monthly, bi-weekly or weekly loan payments, total interest, extra payments and an amortization schedule.

Built and reviewed by Naqash Thaheem, Technical Project Manager. Last reviewed 2026-09-24.