Date Difference Calculator
Days, weeks, months and business days between any two dates, plus date arithmetic.
Calculate the Days Between Two Dates
Counting days between dates by hand is error-prone because months have different lengths and leap years break any simple arithmetic. Project deadlines, contract notice periods, visa durations and payment terms all depend on getting it exactly right.
This calculator gives the span in days, weeks, months and business days, and separately lets you add or subtract a number of days from a date to find a deadline. Business days exclude Saturdays and Sundays, which is the definition used in most commercial contracts.
Key features
- Multiple units at once — days, weeks, calendar months, hours and minutes.
- Business-day count — weekends excluded, which is how notice periods and payment terms are usually written.
- Inclusive option — count the end date as a full day, as many contracts require.
- Date arithmetic — add or subtract any number of days to find a deadline, with the weekday named.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Date Difference Calculator
- Pick the start and end dates
Order does not matter — the tool always reports a positive span. - Decide whether the end date counts
Tick the inclusive box if the final day should be counted, which is common in contractual notice periods. - Read the breakdown
The cards show days, weeks and business days; the table adds calendar months, hours and weekend days. - Use the offset panel for deadlines
Enter a positive number to move forward or a negative one to move back, and the result names the weekday.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Calculators |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
What counts as a business day?
Monday to Friday, excluding Saturday and Sunday. This tool does not subtract public holidays, because those differ by country, region and sometimes industry — check your local calendar for anything contractual.
Should the end date be included?
It depends on the wording. "Within 30 days" usually excludes the start date and includes the end date; "30 days from" usually starts counting the following day. The inclusive toggle lets you match whichever rule applies.
Why does the month count seem off by one?
Calendar months only increment once the same day-of-month is reached. From 31 January to 1 March is one month and one day, not two months, because 28 February has not completed a second month.
Does it handle leap years?
Yes. All arithmetic uses real calendar dates, so 29 February is counted whenever it falls inside the range.