How to use the Date Difference Calculator
- In Days between dates, pick a start and end date. Tick Include end date if both the first and last day should count (e.g. for a holiday or rental period).
- Read the total days plus the breakdown in years/months/days, weeks, business days and weekend days.
- Switch to Add / subtract days to find the date that is, say, 90 days or 6 weeks from a given day — optionally counting only business days.
- Use Countdown to see the live time remaining until a deadline, launch or holiday. Dates are kept in the URL, so you can share the result.
How to calculate the days between two dates
The number of days between two dates is the end date minus the start date. By default this calculator excludes the end date, the same convention as spreadsheets (=B1-A1 in Excel or Google Sheets) and most programming languages: from Monday to Friday of the same week is 4 days. Tick Include end date when you’re counting calendar days that both count — a hotel stay from the 1st to the 5th is 4 nights, but a festival running from the 1st to the 5th lasts 5 days.
All calculations use calendar dates in UTC, so daylight-saving changes never add or remove an hour, and leap years (2028 has 29 February) are handled automatically.
Years, months and days breakdown
Months have 28 to 31 days, so “1 month” isn’t a fixed number of days. The breakdown counts whole years first, then whole months, then the remaining days — the way you’d calculate someone’s age. From 31 January to 1 March 2026 is 1 month and 1 day; from 15 March 2024 to 25 October 2026 is 2 years, 7 months and 10 days.
Business days
Business days count Monday to Friday and skip Saturdays and Sundays. They don’t subtract public holidays, which differ by country and region — subtract those yourself (for example, a 22-business-day month with one bank holiday has 21 working days). With Include end date off, the end date isn’t counted, which matches “how many working days until the deadline”.
Adding and subtracting time
Years and months are added first, then weeks and days. If the target month is shorter, the date is clamped to its last day: 31 January + 1 month = 28 February (29 in leap years). With business days ticked, the days field skips weekends — 5 business days after Friday is the following Friday. This is handy for payment terms (“net 30”), notice periods, shipping estimates and project plans.
Examples
| Question | Answer |
|---|---|
| Days from 1 Jan 2026 to 1 Jan 2027 | 365 days (52 weeks, 1 day) |
| Business days in October 2026 (1–31, incl. end) | 22 |
| 90 days after 25 Oct 2026 | Sat, 23 Jan 2027 |
Need to convert a date to a Unix timestamp or compare times across countries? Use the Unix Timestamp Converter and the Time Zone Converter.
Tools that pair well with the Date Difference Calculator
- Percentage Calculator — Seven everyday percentage calculations on one page.
- Cron Expression Generator — Build a crontab schedule without memorising the syntax — or paste an existing expression to see what it means in plain English and exactly when it will run next.
- Unit Converter — Convert between metric, imperial and technical units in ten categories — with a two-way converter and a table of every unit at once.
- Aspect Ratio Calculator — Resize images and videos without distortion: fill in a ratio and one side to get the other, or enter a size to find its ratio — with ready-to-paste CSS.