Days Between Dates

Fast Date Duration Calculation

Enter a start and end date to instantly see the number of days, weeks, approximate months, weekdays, and weekend days between them. The calculator automatically swaps the dates if you enter them in reverse order.

How It Works

Days = (End Date − Start Date) in milliseconds / 86,400,000 Weeks = Days / 7 Weekdays = count of Mon–Fri in range Weekends = count of Sat–Sun in range

Quick Reference: Common Durations

Duration	Days	Weekdays
1 week	7	5
1 month (avg)	30.44	~22
Quarter (90 days)	90	~65
1 year	365 or 366	~261

Frequently Asked Questions

There are 364 days between January 1 and December 31 (not including January 1, but including December 31). If you want to include both the start and end date, the answer is 365 (or 366 in a leap year).

A typical year has approximately 260–262 working days (365 days minus 52 weekends = 261 weekdays). After accounting for approximately 10 federal holidays in the US, the net working days are roughly 251. Exact numbers vary by year and location.

Add 1 to the result. This calculator counts the gap between dates (like the space between fence posts). To count both the start date and end date, add 1. For example, a project running from Monday to Friday spans 4 days in our calculator but includes 5 days of work.

January, March, May, July, August, October, and December each have 31 days — the longest months. February has the fewest: 28 days (29 in a leap year). The average month has approximately 30.44 days.