Date & Time
Date Difference Calculator
Count the days between two dates, with a breakdown into years and months, the number of weekdays and weekend days, and an option to include the end date for leave or booking calculations.
How to use this calculator
- Set the start date, or leave it as today.
- Set the end date.
- Turn on the include end date option if both the first and last day should be counted, as leave applications usually require.
Formula
Days = (End date − Start date) ÷ 86,400,000 (plus 1 when counting inclusively)
- 86,400,000
- milliseconds in a day, used to convert the difference into whole days
- Inclusive
- adds one day so that both the start and end dates are counted
Dates are compared at midnight UTC so that daylight saving changes cannot shift the count.
Worked example
Leave from 1 October 2026 to 10 October 2026, counting both days.
- Exclusive difference10 October − 1 October = 9 days
- Inclusive9 + 1 = 10 days
- Weekend days in range4 October and 10 October fall on a weekend
Ten calendar days of leave, of which eight are weekdays.
Inclusive and exclusive counting
There are two correct ways to count days between dates, and they differ by one. Exclusive counting measures the gap: from Monday to Friday is four days. Inclusive counting counts both endpoints: Monday to Friday is five days of leave.
Hotels charge by nights, which is exclusive. Leave applications, project durations and event days are usually inclusive. Use the toggle to switch between them rather than adding one by hand.
Working days
The weekday count treats Monday to Friday as working days and excludes Saturday and Sunday. It does not exclude public holidays, which vary by country, state and organisation, and it does not know about six-day weeks, which are still common in parts of India.
Things to keep in mind
- Public holidays are not excluded from the weekday count.
- If the end date is before the start date, the calculator still gives the gap and notes that the order is reversed.
Frequently asked questions
Should I include the end date when applying for leave?
Usually yes. If you are away from 1 October to 10 October, both days are days you are not at work, so that is ten days of leave. Turn on the include end date option for this.
How many working days are there between two dates?
The result shows weekdays from Monday to Friday in the range. Subtract any public holidays and, if your workplace has a six-day week, treat Saturdays separately.
Was this calculator useful?
Quick reaction, a note, or both — whatever's useful to you.
Contact details are optional and only used to reply to you — never shared, never used for marketing.