How to count days between dates
Subtract the earlier date from the later one to count calendar days. Date arithmetic is surprisingly fiddly because months have different lengths and leap years add a day every four years — the calculator handles all of that automatically.
People use date differences for many things: counting down to a deadline or event, calculating notice periods, tracking project timelines, measuring a stay, or working out how long until a delivery. If you need only business days, count the weekend days within the range and subtract them — or use a working-days calculator if this one does not match your need.
Date facts
- A year is 365 days, or 366 in leap years
- A week is exactly 7 days
- Feb 29 occurs in years divisible by 4 (with century exceptions)