Guide

How to Count Days Between Dates

Learn when to include the end date, how calendar days differ from business days, and how date calculators work.

Counting days sounds simple until you need to decide whether the start and end dates should both count. A hotel stay often counts nights, while a school assignment may count calendar days including the final date.

Business day calculations are different again. They usually exclude weekends and may also exclude public holidays. This site's first business-day tool excludes Saturdays and Sundays only, which keeps the calculation transparent.

When a date calculator adds months or years, month-end dates need care. Adding one month to January 31 cannot always preserve the same day number because February has fewer days.