Slopculator · free, in your browser

Date calculator: days between two dates

Type a date sum the way you would say it: the days between two dates, a date plus 90 days, or a deadline minus two weeks. Slopculator answers as you type and keeps a paper tape.

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How to do it

1. Open Slopculator and click in Type a calculation.
2. For the days between two dates, type the later date minus the earlier one: 2026-12-25 - 2026-10-11 gives 75 days.
3. To add or take away time, type a date plus or minus days, weeks, months or years: today + 90 days, or 2026-03-01 - 2 weeks.
4. Put in weeks or in years at the end to change the unit: 2026-12-25 - today in weeks.
5. Press Enter to put the line on the paper tape. When the answer is a date, Add to Calendar saves it as an all-day event.

Your files stay on this device: Slopculator runs in your browser, with no upload, no account and no watermark.

Questions

What happens when I add a month to 31 January?

The date stops at the last day of the month, so 2026-01-31 + 1 month is 2026-02-28.

Which date format should I type?

Year, month and day with hyphens, such as 2026-10-24. The word today also works and means the current date on your device.

Does it count both the first and the last day?

It gives the plain difference, as a subtraction does: from 2026-10-11 to 2026-12-25 is 75 days. Add 1 if you want to count both ends.

Can it work out an age?

Roughly: today - 1990-05-17 in years gives the years as a decimal, using an average year of 365.2425 days.

More with Slopculator

• Time calculator: add and subtract hours and minutes
• Percentage calculator
• Unit converter with exact factors

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