The one thing everyone gets wrong: inclusive vs exclusive counting
From Monday to Wednesday, is that 2 days or 3? Both answers are used — for different things. The difference is 2 days (Wednesday minus Monday) and that is what deadlines and notice periods usually mean. The count of calendar days touched is 3 (Mon, Tue, Wed), which is what hotel stays and leave balances often use. The checkbox above switches between the two so you can match the convention your situation uses.
Worked example
1 January 2026 to 31 January 2026 is a difference of 30 days, or 31 days if you include the end date. There are 22 business days (Monday–Friday) strictly between those dates.
Common uses
Contract deadlines, project timelines, notice periods at work, probation and visa windows, pregnancy and event countdowns (see the Age Calculator for birthdays), and checking exactly how long a warranty or subscription really lasts.
Frequently asked questions
Does this calculator count weekends?
The total-days figure counts every calendar day. The business-days figure counts only Monday to Friday between the two dates (public holidays are not deducted, as they differ by country).
What if I pick the end date before the start date?
The calculator swaps them and tells you it did, so you still get the correct positive difference.
How are leap years handled?
They are simply real calendar days — a span crossing 29 February includes it, so the count is exact.
Why does my employer count differently?
Many employers count inclusively (both the first and last day) for leave. Tick the 'include the end date' box to match that convention.