Date Difference Calculator

Guide: Date Difference Calculator

Two tools in one

The first card counts the time between two dates; the second adds or subtracts an amount from a start date. Both update as you type and use calendar days, never clock hours, so daylight saving never affects them.

How the difference is computed

• Total days = (end − start) in whole days, plus 1 if you include the end date.
• Weeks and days = total days ÷ 7 with the remainder.
• Years, months, days = calendar subtraction with borrowing: if the day difference is negative, add the length of the month before the end date and take one month away.
• Business days = the number of Monday-to-Friday dates in the range, start date included.

Adding and subtracting

Days and weeks are plain arithmetic on the date (a week is 7 days). Months and years keep the same day number when possible and clamp to the last day of a shorter month, which is the rule most spreadsheets use. Business days skip Saturdays and Sundays one working day at a time, so adding 1 business day to a Friday gives Monday.

Tips

For deadlines that exclude public holidays, subtract the holidays from the business-day count by hand. If the start date is after the end date the tool swaps them and tells you. Use Copy result to paste the answer into an email or a ticket.

FAQ

Does the calculator include the end date?

By default the end date is not counted, so Jan 1 to Jan 8 is 7 days. Choose "include end date" to count both ends (8 days).

How are business days counted?

Monday to Friday count; Saturday and Sunday do not. Public holidays are not removed because they differ by country.

What happens when I add a month to Jan 31?

The day is limited to the last day of the target month, so Jan 31 plus one month is Feb 29 in 2024 and Feb 28 in 2025.

Can I subtract from a date?

Yes, switch the operation to Subtract. It works for days, business days, weeks, months and years.

Does daylight saving time change the result?

No. Dates are treated as calendar days, so a 23- or 25-hour day still counts as one day.