How do I count days between two dates?

Subtract the earlier date from the later date and divide by the number of milliseconds in a day (86,400,000). For an inclusive count, add 1 to the result.

What is the difference between inclusive and exclusive day counting?

Exclusive counting counts only the days between two dates, not including either endpoint. Inclusive counting includes both the start and end dates. For example, Jan 1 to Jan 3 is 2 days exclusive but 3 days inclusive.

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Day Counter Calculator

Count the number of days between two dates, or find out how many days until (or since) a specific date. Includes weeks, remainders, and day names.

Days Between Dates

Start Date

End Date

Inclusive (count both start and end dates)

About the Day Counter Calculator

The day counter makes it simple to calculate the exact number of days between any two dates or from today to a future or past event. The inclusive option is useful when you want to count both the first and last day — for example, when calculating how many days a project spans including both the start and end dates. If you want to find out what day of the week a specific date falls on, the Day of the Week Calculator provides that and more, including ISO week numbers.

Common use cases include countdown timers for events like birthdays, holidays, or deadlines; calculating project durations; or figuring out how many days have passed since a past event. All calculations happen in your browser using local dates, so no data is sent to any server. For scheduling across time zones, pair this with the Time Zone Calculator to coordinate dates across different regions.

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Take this calculation further

Browse the other calculators collection for more tools in this subject.

For a related calculation, use Day of the Week Calculator to find the day of the week for any date, plus ISO week number, day number in year, and days until next occurrence. Alternatively, use Time Calculator to add, subtract, or find the difference between times in hours, minutes, and seconds.

For the underlying method, read How Age Calculation Works: Chronological Age, Leap Years, and Cultural Differences or Date Math Explained: Counting Days, Adding Time, and Finding Weekdays.