Date Difference Calculator
The date difference calculator computes the exact time span between any two dates. Get results in years, months, and days, plus total days and total weeks.
Useful for calculating age, project durations, contract lengths, or the time between any two events. Simply enter a start and end date to see the full breakdown.
How it works
The difference is computed by calendar arithmetic: years, months, and remaining days between the two dates. Total days = absolute difference in calendar days. Total weeks = total days ÷ 7 (rounded down).
Use cases
- Calculating time between two events
- Determining contract or lease duration
- Computing project timelines
- Finding the number of days until a deadline
Frequently asked questions
How do I calculate the number of days between two dates?
Enter a start date and an end date, and the calculator returns the total number of calendar days between them, along with the breakdown in years, months, and days. Internally it counts the absolute difference in calendar days, so it correctly handles months of different lengths and leap years.
Does the calculator include leap years?
Yes. Because it uses actual calendar arithmetic rather than a fixed 365-day year, any February 29 that falls within your range is counted. This makes the total-days and total-weeks results exact for any span, including multi-year periods.
How do I convert the day count into weeks?
Divide the total number of days by 7, and the calculator rounds down to whole weeks. For example, 30 days equals 4 weeks (with 2 days left over). The tool shows total weeks alongside total days so you do not have to do the division yourself.
Is the end date included in the difference?
The calculator measures the span from the start date to the end date, so the result is the number of full days between them. If you need to count both endpoints as occupied days, for example when counting billable or vacation days, add one to the total.
Can I use this to calculate someone's age?
Yes. Enter the birth date as the start and today's date as the end, and the years-months-days breakdown gives the exact age. This is the same calendar arithmetic used by formal age calculations, so it stays accurate across leap years and varying month lengths.