Days Between Dates Calculator
Pick a start date and an end date to see the gap in days, weeks, months and years.
Your details
Result
Fill in the fields to see your result.
Good to know: From 1 January to 31 December is 364 days, or 365 counting both end dates.
About this tool
Calculate the number of days between two dates, or add/subtract days from a date — for deadlines, planning, and scheduling.
Formula
Days between = end date - start date (in milliseconds, converted to days). 1 day = 86,400,000 ms.
Reference values
- 1 year ≈ 365 days (non-leap)
- 1 week = 7 days
- Leap years add 1 day every 4 years
Questions people ask
Does it include the start and end date?
The count is the difference between the dates. Add 1 if you want to include both days.
Does it account for leap years?
Yes, it counts 29 February when it falls within the range.
Can I add or subtract days from a date?
Use the add/subtract option to find a future or past date.
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How we calculate this
We use the standard published formula or definition for this calculation, and we show the working so you can check it.
Spotted a mistake? Tell us and we'll check it. How we check our calculators