Free Date Calculator
Find the difference between two dates, or add/subtract time from a date — no signup, nothing sent to a server.
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Years
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Months
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Days
Total days: —
Total weeks: —
How to use the date calculator
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1
Pick a calculation type
Choose "Difference between dates" or "Add / subtract from a date" from the tabs above.
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2
Enter your dates
Fill in the date fields — for add/subtract, also enter how many years, months, weeks, or days.
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3
Read the result
The answer updates instantly, ready to use.
Example use cases
Project deadlines
Work out a due date by adding a number of weeks or days to a start date.
Contract & lease terms
Find the exact number of days or months between a start and end date.
Event & trip planning
Count down the days remaining until a specific date.
Billing & invoicing cycles
Calculate a due date a fixed number of days after an invoice date.
Frequently asked questions
How is the difference between two dates calculated?
The calculator counts full years, then full months, then remaining days between the start and end date, the same way you'd count on a calendar — plus a total-days and total-weeks figure.
How does adding or subtracting months and years work?
Months and years are added calendar-wise (e.g. Jan 31 + 1 month lands on the last valid day of February), then weeks and days are added on top as exact 7-day and 1-day increments.
Does it account for leap years?
Yes. All calculations use real calendar dates, so leap years are handled automatically.
Are my dates sent to a server?
No. Every calculation runs entirely in your browser — nothing is transmitted or logged.