Date Calculator
Calculate date differences, add/subtract dates and time periods.
Date Calculator
Calculation History
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Date Difference
- • Calculate days between dates
- • Shows weeks, months, years
- • Handles leap years
- • Absolute difference calculation
Add/Subtract Days
- • Add days to a date
- • Subtract days from a date
- • Automatic month/year rollover
- • Leap year handling
Privacy & Features
- • 100% client-side calculations
- • No data sent to servers
- • Calculation history
- • Works offline
About the Date Calculator
The Date Calculator works out the difference between two dates, or adds and subtracts days, weeks, months, and years from a date. It answers questions like "how many days until?" or "what date is 90 days from now?" without manual counting.
Date math is deceptively tricky thanks to varying month lengths and leap years. Whether you’re counting down to a deadline, figuring out an age, or scheduling something a set period ahead, the calculator gets it right instantly.
Everything runs in your browser with no upload or account. Enter your dates and get accurate results immediately.
How to use the Date Calculator
- Choose whether to find the difference between two dates or add/subtract a period.
- Enter the start date.
- Enter the second date, or the amount of time to add or subtract.
- Calculate the result.
- Read the number of days (or the resulting date).
Common use cases
- Counting the days until a deadline or event.
- Calculating someone’s age from their birth date.
- Finding the date a set number of days in the future or past.
- Working out durations between two dates for billing or planning.
Frequently asked questions
Does it account for leap years?
Yes. Date calculations handle leap years and varying month lengths so the results are accurate.
Can I add months and years, not just days?
Yes. You can add or subtract days, weeks, months, and years from a starting date.
Does it count inclusive or exclusive of the end date?
The difference is the span between the two dates; check the result to see how the endpoints are counted for your specific need.
Is anything uploaded?
No. Calculations run in your browser, so nothing leaves your device.
Can it calculate business days only?
It focuses on calendar dates; for workday-only counts you’d need to account for weekends and holidays separately.