Date Duration Calculator

How to use the date duration calculator

Choose a start date and an end date. The calculator counts the days between them and converts the result into weeks, months, years, hours and minutes. It also counts how many of those days are weekdays.

Should I include the end date?

By default the count works like subtraction: from Monday to Wednesday is 2 days. Choose Yes, add 1 day when both the first and last day should count, for example a hotel booking or an event that runs from the 1st to the 5th (5 days).

How to count days between dates by hand

1. Count the days left in the start month after the start date.
2. Add the full days of each month in between (31, 28 or 29, 30 …).
3. Add the day number of the end date.

From January 1 to March 15, 2026: 30 days left in January + 28 in February + 15 in March = 73 days.

Month	Days
January, March, May, July, August, October, December	31
April, June, September, November	30
February	28 (29 in a leap year)

Uses for a date duration calculator

• Days until a vacation, wedding or due date
• Length of a contract, lease or project
• Days since an event, such as a quit date or anniversary
• Interest periods and late fees
• Tracking streaks and habits

Frequently asked questions

How many days are between two dates?

Enter both dates in the calculator. It subtracts the start date from the end date and handles different month lengths and leap years for you.

How many weekdays are between two dates?

The Weekdays row counts Monday to Friday only. It does not skip public holidays, which vary by country and company.

Why is the month count approximate?

Months have 28 to 31 days, so converting days to months uses the average month length of 30.44 days. The years, months, days row gives the exact calendar breakdown.

Can the end date be before the start date?

Yes. The calculator swaps them and shows the duration as a positive number.

Does it count leap days?

Yes. February 29 is counted in leap years.