Date Difference Calculator
Calculate days, weeks, months, and years between two dates. Includes business days and add/subtract. 100% client-side.
Difference
30days
⏱ Total in every unit
Weeks
4
Days
30
Hours
720
Minutes
43,200
Seconds
2,592,000
💼 Business days
Business days
21
Weekend days
9
➕ Add or subtract from a date
Result date
2026-11-10
Tuesday, November 10, 2026
🔒 100% private: All calculation happens in your browser. Your dates never leave your device.
About Date Difference Calculator
Calculating the difference between two dates is one of the most common date operations — for contracts, projects, eligibility periods, deadlines, and time tracking. But calendar math is not trivial: months vary in length (28–31 days), leap years add an extra day, and "difference in months" can mean different things depending on context. This tool gives you the exact difference in years, months, and days (like age calculation), plus the total in every other unit: weeks, days, hours, minutes, seconds. It also computes business days (excluding weekends) — useful for calculating working days on a project. And it can add or subtract days from any date to find a future or past deadline. Everything runs in your browser.
How It Works
- Enter the start date and end date.
- See the difference broken down into years, months, and days.
- Scroll down for totals in other units (weeks, hours, minutes, seconds).
- Check the business days count (excluding weekends).
- Use the "Add/Subtract days" section to find a date offset from any start date.
✨ Key Features
- ✓Difference in years, months, and days
- ✓Total weeks, days, hours, minutes, seconds
- ✓Business days (excluding Sat/Sun)
- ✓Optional custom weekend days
- ✓Add or subtract days/weeks/months/years from a date
- ✓Start/end date order auto-detected
- ✓Leap year aware
- ✓Copy any value
- ✓Multiple preset shortcuts (today, tomorrow, next week)
- ✓100% client-side — no data sent to any server
🎯 Common Use Cases
- →Calculating project or contract duration
- →Finding the number of working days between two dates
- →Determining eligibility periods (age, residency)
- →Planning deadlines and milestones
- →Calculating vacation days or notice periods
- →Tracking time between events (health, legal)
- →Finding how many days until a future date
- →Adding or subtracting days for scheduling
💡 Advanced Tips & Pro Insights
- ▸"Difference in months" is ambiguous — this tool uses completed calendar months. If start is Jan 15 and end is Feb 14, the difference is 0 months and 30 days (the month is not yet complete).
- ▸Business days exclude Saturday and Sunday by default. Some countries have different weekends (e.g., Friday–Saturday in parts of the Middle East). Custom weekends are supported.
- ▸Leap years add an extra day every 4 years (except centuries not divisible by 400). This tool handles leap years automatically.
- ▸For time-sensitive calculations, use a time-zone-aware tool — this tool uses local date only (no timezone offset).
- ▸Adding months is tricky: adding 1 month to Jan 31 gives Feb 28 (or 29 in leap years) — there is no Feb 31.
Frequently Asked Questions
Is this date difference calculator free?▾
Yes, this date difference calculator is completely free with no signup, email, or usage limits.
Is my data safe?▾
Yes, 100% safe. All calculation happens in your browser. Your dates are never sent to any server.
How is the difference calculated?▾
The difference is calculated in completed calendar units: completed years, then months, then days. For example, Jan 15 to Mar 14 is "1 month 27 days" (not 2 months, since Mar 15 would complete the 2nd month).
Does the tool include the end date or not?▾
By default, the calculation is "exclusive of end date" — the difference between 2026-01-01 and 2026-01-05 is 4 days (not 5). This matches the common "days between" convention. If you need inclusive, add 1 to the result.
What are business days?▾
Business days (also called working days) exclude weekends — typically Saturday and Sunday. Some industries and countries have different weekends (e.g., Friday–Saturday). This tool lets you configure which days count as weekend.
How do leap years affect the calculation?▾
Leap years add Feb 29. If your date range spans a leap year, the total days reflect that extra day. For example, Feb 28 to Mar 1 is 2 days in a leap year (Feb 29 included), but 1 day in a non-leap year.
Can I add or subtract days from a date?▾
Yes. Scroll down to the "Add / Subtract" section. Enter a start date and the number of days (or weeks/months/years) to add or subtract. The result appears instantly.
Does the tool handle daylight saving time?▾
No — this tool works with calendar dates only (no time component). DST affects times, not dates. For time-based differences across time zones, use our Time Zone Converter.