Date difference
Count calendar days between two dates and explore the range on a calendar.
How it works & useful details
How it works & limits
The signed difference is end date minus start date. The large count is its absolute magnitude, optionally plus one to include both dates. A same-day range has a difference of zero or an inclusive count of one.
These are calendar dates, not elapsed hours. Timezones and daylight saving do not change the count. Enter YYYY-MM-DD, years 0001–9999.
Your working space
Explore the live preview, then save a copyable text report. Inputs stay on this device and are cleared by refreshing. Dates use the Gregorian calendar, including before its historical introduction.
About this tool
Date difference counts the calendar days between two dates and shows the range on a calendar so you can see exactly which days it covers. It answers questions like how long a project ran or how many days a policy is valid.
The count uses calendar days rather than elapsed hours, so it is not affected by daylight saving changes. Everything is calculated locally with the Gregorian calendar.
How to use it
- Enter the first and second date.
- Choose whether the count is inclusive of the endpoints.
- Read the total days and, where relevant, the breakdown in weeks and months.
- Inspect the range on the calendar to confirm the span.
Worked example
From 2026-01-01 to 2026-12-25 there are 358 calendar days, or 51 weeks and 1 day. If both dates should count, as for an event that runs on both the first and the last day, turn on the inclusive option to get 359.
The signed difference is end minus start. Reversing the dates gives −358, which is useful for checking whether a deadline has passed.
Inclusive vs. exclusive counting
"How many days between Monday and Friday?" has two reasonable answers. Four is the number of midnights crossed, which is right for hotel nights and elapsed time. Five is the number of dates touched, which is right for a conference or leave days. The exclusive count is the default because it matches subtraction. Pick inclusive when you are counting dates rather than gaps.
The count uses calendar dates only. Time zones and daylight saving do not change it, which also means it is not a count of elapsed 24-hour periods between two clock times. Use the duration calculator for hours and minutes.
Frequently asked questions
Why does the day count differ from my own counting?
The endpoint rule matters. Include or exclude the start and end dates depending on how your deadline is defined.
Does it account for time zones?
No. Dates are treated as calendar dates without time-of-day or time-zone conversion.
Can I compare dates in the past?
Yes. Historical and future dates are supported within the tool’s date limits.
Can I count only working days?
Use the business days calculator for that. It excludes weekends and any holiday dates you supply.