Web Tools
Date Difference Calculator
Calculate the exact duration between two dates in years, months, days, weeks, hours, minutes, and seconds. Add or subtract days from a date. Handles leap years correctly. Runs entirely in your browser — your data never leaves your machine.
date difference duration calendar time calculator days
Published May 31, 2026
All interactive tools run entirely in your browser. Your data never leaves your device.
How It Works
Select two dates to calculate the exact duration between them. The calculator breaks down the result into years, months, days and also shows totals in weeks, hours, minutes, and seconds. Use Add/Subtract mode to find a future or past date.
Features
- Full breakdown: years, months, and days with total equivalents
- Multiple units: total days, weeks, hours, minutes, seconds
- Add/Subtract mode: add or subtract days from any date
- Leap year aware: correctly handles Feb 29 and varying month lengths
- Auto-swap: if end date is before start, dates are swapped automatically
- Today button: quickly insert today’s date
- Human readable: natural language summary (e.g., “2 years, 3 months, 5 days”)
- 5 examples: common date range scenarios
- Private: runs entirely in the browser — no data transmitted
Use Cases
- Calculating age or time until an event
- Project duration estimation and deadline tracking
- Determining days between contract dates
- Finding exact gaps between historical events