Date Difference Calculator
Calculate exact days, weeks, months, and years between any two dates instantly.
Date Difference Calculator
Date Range
Pick start and end dates
Time Between Dates
Smart Insights
Personalized takeaways from your numbers.
Real-Life Examples
Jan 1 to Mar 31
90-day sprint
The Formula Behind It
Difference = End Date − Start DateHow It Works
- Enter the start date of your range.
- Enter the end date (or leave blank for today).
- Optionally include the end date in the count.
- View total days, weeks, and years/months/days breakdown.
About Date Difference Calculator
The Date Difference Calculator computes the exact time span between any two calendar dates — in days, weeks, months, and years. Perfect for contract deadlines, rental periods, project planning, event countdowns, and legal date calculations.
How Date Math Works
We calculate the difference using calendar dates, correctly handling varying month lengths and leap years. The breakdown shows whole years, months, and remaining days for an intuitive reading alongside the total day count.
Inclusive vs Exclusive Counting
By default, we count the span between dates (exclusive of the end date in the day count sense). Enable include end date to add one day — useful when both the start and end dates should count (e.g., a 7-day rental from Monday to Sunday inclusive).
Common Use Cases
Calculate days until a deadline, determine employment tenure, measure project duration, count days in a billing period, verify age eligibility between dates, and plan event timelines. For birth-date age calculation, see our dedicated Age Calculator.
Frequently Asked Questions
How do I calculate days between two dates?
Enter a start date and end date. We compute the exact calendar difference including leap years.
Does the calculator include the end date?
Results show the span between dates. Toggle inclusive counting in the form if you need to count both endpoints.
Can I calculate business days only?
This version counts all calendar days. Business-day mode may be added in a future update.
How are months calculated?
We show whole months/years plus remaining days for an intuitive breakdown.
Does it handle leap years?
Yes. February 29 and varying month lengths are handled correctly.
Can I use this for project deadlines?
Absolutely. Great for contracts, rentals, events, and project planning.
What timezone is used?
Calculations use your browser's local timezone at midnight for each date.
Can start date be after end date?
Yes. We show the absolute difference and indicate direction.
How is this different from the age calculator?
Age calculator is optimized for birth dates. This tool works for any two dates.
Is historical date math supported?
Yes, for dates supported by the JavaScript Date object (roughly year 100–275760).