What this calculator shows
Use two dates to measure a birthday, relationship, project, notice period, exam deadline, retirement date or any other milestone. The result gives a calendar-accurate years–months–days breakdown as well as total days and complete weeks.
The calculation runs in your browser. Dates are not uploaded or stored by this page.
How to calculate the difference between dates
- Enter the earlier date and later date.
- Use a Today shortcut or swap the dates if needed.
- Read the signed direction, calendar duration, total days and total weeks.
Important counting note
This tool measures elapsed calendar time. A contract, government notification or legal deadline may count the first and last day differently. Treat this result as a planning aid and follow the organisation’s stated counting method for official use.
Frequently asked questions
How does the date difference calculator count months?
It uses calendar months and adjusts for different month lengths. The result is shown as completed years, months and remaining days, alongside total elapsed days and weeks.
Can I compare a past date with today?
Yes. Use the Today shortcut for either date. The result explains whether the second date is in the past or future.
Does it handle leap years and February 29?
Yes. The calculation uses real Gregorian calendar dates and handles leap years, month ends and February 29.
Is the result suitable for an official deadline?
It is a mathematical date calculation. Official organisations may use inclusive counting or their own deadline rules, so follow the relevant notice.