How to use the days between dates calculator
- Pick a start date and an end date.
- See the gap instantly in days, weeks, months and years.
- Tick "include the end day" if you want both the first and last day counted (useful for booking nights, leave days or event durations).
How the date difference is calculated
By default the tool counts the full days from the start date up to — but not including — the end date, the way you'd count nights between a check-in and check-out. The total days figure is exact; weeks, months and years are derived from it (a month is treated as about 30.44 days and a year as 365.25 days on average), so those are close approximations rather than calendar-exact counts. Everything runs in your browser, so your dates are never uploaded.
Benefits
- Counts the exact number of days between any two dates instantly.
- Also shows the gap in weeks, months and years.
- Option to include the end day for durations like hotel nights or leave.
- Runs in your browser — your dates are never uploaded. Free and unlimited.
Limitations to know
- Weeks, months and years are derived from the day count using averages, so they are close approximations, not calendar-exact.
- It works from calendar dates and ignores time of day and time zones.
- It does not calculate business days only (it counts every day).
Common mistakes to avoid
- Forgetting whether you want the end day included — a hotel stay counts nights (end day excluded), an event may count both days.
- Swapping the start and end dates (the tool handles it, but check which direction you meant).
- Treating the approximate months/years figure as an exact calendar count.
Alternatives
To find someone’s age from a birth date, use the Age Calculator. For general percentage math, use the Percentage Calculator.
Last updated: August 2026 · Reviewed by the AI Toolbox editorial team.
Frequently asked questions
Does it count the end day?
By default no — it counts full days between the two dates (like nights in a hotel). Tick "include the end day" to count both the first and last day.
Are my dates stored anywhere?
No. The whole calculation runs in your browser and nothing is uploaded.
Does it handle leap years?
Yes — the day count uses real calendar dates, so leap years and different month lengths are handled automatically.