Date Arithmetic Made Simple
A date calculator answers the two questions that come up constantly when planning: what date is it after adding some time, and how many days separate two dates. This free tool does both, using the real calendar so leap years and uneven month lengths are always handled correctly.
The first section adds or subtracts days, weeks, months and years from any starting date. Use it to find a delivery date, a project deadline, a due date or an expiry date. The second section counts the exact days between two dates and shows the same span in weeks and months, which is handy for travel, payroll or simply knowing how long something took.
Everything runs in your browser, works on any phone or computer, and needs no sign-up. Results appear instantly and follow the current language selection.
How to use it
- To add or subtract time: choose a date, an amount, a unit and a direction, then calculate.
- To find the gap: choose the two dates in the second section and calculate.
Frequently asked questions
How do I add days to a date?
Pick a start date, enter a number, choose days, weeks, months or years and select add. The tool shows the resulting date and its day of the week.
How do I find the days between two dates?
Use the second section. Pick both dates and the tool returns the exact number of days between them, plus the equivalent weeks and months.
Does it handle leap years?
Yes. All calculations use the real calendar, so leap years and different month lengths are handled automatically.
Can I subtract time from a date?
Yes. Choose subtract instead of add and the tool moves the date backwards by the amount you enter.
Results are for planning and reference. Confirm critical dates with official sources when required.