Date Difference Calculator
Count the time between two dates. Pick a start and end date to see total days, weeks, and business days (Monday–Friday).
Duration
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Check it outCounting days the right way
Total days count every calendar day between your dates. Business days exclude Saturdays and Sundays — useful for delivery windows, project deadlines, and payment terms like “net 30.” Note that public holidays aren't removed, so subtract any that fall in your range for an exact working-day count.
How it’s calculated
Difference mode: days = end − start. Business days count weekdays (Mon–Fri) only; public holidays are not excluded. Add/subtract mode: years and months use calendar-aware arithmetic (e.g. adding 1 month to January 31 lands on the last valid day of the resulting month), weeks add 7 days per week, and plain days shift the date by the exact number of calendar days. When “business days only” is selected for the days unit, the date steps one calendar day at a time and only counts a step once it lands on a weekday, continuing until the requested number of business days has been counted — the same weekday-only definition used by the business-days result above.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Worked example
From today to 30 days out is 30 days, about 4.3 weeks, and roughly 22 business days.
Common mistakes
- Expecting holidays to be excluded from business days.
- Forgetting whether the end date is inclusive.
Frequently asked questions
Are holidays excluded?
No — business days here mean weekdays only. Subtract any public holidays in your range manually.
Is the end date included?
The count is the span between the two dates. Add one day if you need the range to be inclusive of both ends.
Can I go backwards in time?
Yes — the result uses the absolute difference, so order doesn't matter.
Can I add or subtract days from a date?
Yes — switch the calculator to “Add or subtract from a date,” pick a start date, choose add or subtract, enter an amount, and pick days, weeks, months, or years.
What does “business days only” mean when adding to a date?
It steps forward or backward one weekday at a time, skipping Saturdays and Sundays, until it has counted the number of business days you entered. It only applies when the unit is set to days.