Free day counter calculator
Enter a start and end date — this day counter returns the total days between them, with options to include or exclude the start and end date, updated live, as you type.
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Date calculations use calendar days. Working days exclude weekends but not public holidays unless noted.
Results are estimates. Consult a professional.
How the day counter calculator works
Enter a start date and an end date and the calculator returns the number of calendar days between them. You can choose to include both the start and end dates (useful for legal and billing deadlines) or count only the days in between. The result is always a positive number — the order you enter the dates does not matter.
Worked example: project duration from 1 March to 30 June
A project kicks off on 1 March 2026 and the final delivery is due on 30 June 2026. The project manager needs to know the total duration in days.
Common time period durations in days
Not every period converts to a round number of days. This table shows the standard day equivalents for common time spans.
| Period | Days |
|---|---|
| 1 week | 7 |
| 1 month (average) | 30.44 |
| 1 quarter (91 days) | 91 |
| Half year (non-leap) | 182–183 |
| 1 year (standard) | 365 |
| 1 year (leap) | 366 |
Source: Gregorian calendar. Monthly averages use 365.25 ÷ 12. Actual month lengths range from 28 to 31 days.
Tips for counting days accurately
Whether you are tracking a project, calculating an age in days, or verifying a legal notice period, these tips will help you get the right answer.
- Use 'include both endpoints' for legal deadlines — a 30-day notice period that starts on the 1st and ends on the 30th counts 30 days inclusive. Excluding one endpoint would give 29.
- Business days are separate — this calculator counts all calendar days including weekends and public holidays. To exclude them, use the business days calculator.
- Leap years matter over long ranges — between any two dates more than a year apart, check whether a 29 February falls in the span. The calculator includes it automatically.
- Age in days — enter your date of birth as the start and today as the end to find exactly how many days you have been alive.
- Event tracking — count days since a diagnosis, a quit date, or a workout streak to measure progress objectively.
Accuracy and limitations
The day counter uses the proleptic Gregorian calendar and handles leap years correctly, including the century-year rule (years divisible by 100 are not leap years unless also divisible by 400). The result is exact for any date range your browser can represent — typically thousands of years in either direction.
The calculator counts calendar days only — it does not distinguish between business days, working hours, or time zones. If a deadline is defined in business days, or if the start and end events occur at specific times across different time zones, you will need to adjust the result accordingly.
Day counter terms defined
About this day counter calculator
This calculator runs entirely in your browser — nothing you enter is sent to any server.
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