Date Difference Calculator
Calculate the exact number of days, weeks, months, and years between any two dates. Includes business days (weekdays only) mode. 100% browser-based.
Pick a start and end date to see the exact difference
📅 What This Tool Does
A date difference calculator that tells you the exact number of days, weeks, months, and years between any two dates. Enter a start and end date and instantly see the duration broken down into every useful unit — plus a business-days mode that excludes weekends for work deadlines and SLA tracking.
It handles leap years, month lengths, daylight saving, and backward ranges automatically. No approximations, no rounded guesses — just exact calendar math. Everything runs in your browser: your dates are never sent anywhere.
📝 Example
Input
Start: January 1, 2024
End: March 15, 2026
Output
2 years, 2 months, 14 days
804 total days
114 total weeks
574 business days
230 weekend days
⚡ How to Use
- Pick a start date using the first date picker
- Pick an end date — it can be in the past or future
- See the exact breakdown — years, months, days, plus total days, weeks, months, hours, minutes, and seconds
- Check business days if you're tracking work deadlines — the tool auto-excludes Saturdays and Sundays
- Swap dates with the arrow button, or use quick presets like "Today → Christmas" and "Today → New Year"
🎯 Use Cases
💼 Project deadlines
Calculate how many working days you have between today and a launch date. The business-days mode skips weekends automatically.
📦 Shipping & SLA tracking
"Estimated delivery in 5 business days" — pick your order date and count forward to know the exact day, excluding weekends.
🎉 Event countdowns
Days until a wedding, vacation, or graduation. See the exact number of days down to hours, minutes, and seconds.
📊 Anniversaries & milestones
How long since you started a job? How many days have you been married? Great for marking anniversaries.
⚖️ Legal & contracts
Calculate notice periods, contract durations, or statutory deadlines. Accurate to the day across leap years.
🎓 Historical research
"How many days between the moon landing and the Berlin Wall falling?" Answer any historical duration question.
🔒 Privacy
- ✓ All calculations run in your browser
- ✓ Your dates are never sent, stored, or logged
- ✓ Works offline after the page first loads
- ✓ No signup, no ads, no tracking
❓ Frequently Asked Questions
How do I calculate days between two dates?
Subtract the earlier date from the later date. In milliseconds: (date2 − date1) / (1000 × 60 × 60 × 24). This tool does the math for you and accounts for leap years, different month lengths, and daylight saving time automatically. Just pick the two dates and see the exact result.
What is the difference between calendar days and business days?
Calendar days count every day including weekends and holidays. Business days (also called working days) only count Monday through Friday, excluding Saturday and Sunday. Use business days for work deadlines, shipping estimates, and SLA calculations where weekends don't count toward the schedule.
Does this tool include or exclude the end date?
The tool shows BOTH: "inclusive" (both start and end dates counted) and "exclusive" (only the days between them counted). For example, from Jan 1 to Jan 3 inclusive is 3 days, exclusive is 2 days. Pick whichever matches your use case — project deadlines usually use inclusive, duration calculations use exclusive.
How are months and years calculated?
Months and years are calculated using calendar arithmetic, not averaged. If your dates are Jan 15 to March 15, that's exactly 2 months (not 60 days ÷ 30.44). This matches how humans naturally count duration — "two months" means two calendar months, not a fixed number of days.
Can I calculate duration backwards?
Yes. If you put the end date before the start date, the tool swaps them automatically and shows the same absolute duration. You can also use negative values conceptually — "How many days ago was X?" — by putting X as start and today as end.
Does this handle time zones correctly?
The tool uses your local time zone for both dates. If you need to calculate across time zones (e.g., a deadline set in Tokyo from New York), convert both dates to the same time zone first using our Timestamp Converter. For calendar-date calculations (which this tool does), time zones rarely matter.
What about holidays?
Standard "business days" mode only excludes weekends (Saturday and Sunday). It does not exclude national holidays because those vary by country. For accurate working-days calculations in a specific country, subtract your national holidays manually from the result.
Is my data private?
Yes. The calculation runs entirely in your browser. The dates you enter are never sent, stored, or logged anywhere. Works offline after the page first loads.