Date Difference Calculator

Every deadline is a date difference wearing a costume: "due in two weeks", "sixty business days", "until the 29th". The arithmetic looks trivial until leap years, month lengths and weekends get involved - a two-year span can be 730 days or 731, a month can be 28, 29, 30 or 31 days, and a "week" of work is never seven days. Hand-counting past any of these is where errors are born.

Date Difference Calculator computes the exact span between any two dates, with leap years handled automatically. It reports the total days, the weeks and days, the calendar months and years, and the business days - every unit a planner needs - in one view, in either order. Countdowns, contracts and schedules share one correct answer.

• Exact day difference: The span between any two dates.
• Leap years automatic: February 29 handled correctly every time.
• Business days: Mon-Fri counted separately.
• Full breakdown: Days, weeks, months and years in one view.
• Either order accepted: The earlier date is identified.
• Instant results: Updates as you pick the dates.
• Copy or download: The analysis travels with you.
• Free and private: Everything runs in your browser; nothing is uploaded.

1. Pick the first date with the date picker.
2. Pick the second date - either can be the earlier one.
3. Read the total days and which date is earlier.
4. Scan the breakdown - weeks and days, months, years, business days.
5. Copy or download the analysis.

Example 1 - A deadline. From 2026-01-15 to 2026-02-15: 31 days - exactly one calendar month, or 4 weeks and 3 days, 21 business days.

Example 2 - The leap year trap. From 2023-02-27 to 2024-02-27: 366 days, because the span crosses February 29, 2024. The tool handles it; most mental math forgets it.

Example 3 - A project span. From 2026-03-02 (Monday) to 2026-03-13 (Friday): 11 days total but only 10 business days - the difference between a calendar span and a work week.

Example 4 - A long range. From 2020-01-01 to 2030-01-01: 3653 days, 521 weeks and 6 days, 10 years - with the leap years (2020, 2024, 2028) adding the extra days.

Example 5 - Reverse order. Enter the later date first; the tool identifies the earlier one and returns the identical span.

• Leap-year correct: The classic error eliminated.
• All planning units: Days, weeks, months, years, business days.
• Order independent: Either direction works.
• Deadline-ready: Business-day counts for work spans.
• Instant and live: No button presses, no waiting.
• Free and private: Runs entirely in the browser with nothing uploaded.