Should I include the end date?
From 1 October to 3 October is 2 days if you count the difference between the dates, and 3 days if you count both 1 October and 3 October. Use the default for things like "how many days until" or the length of a loan. Tick "include the end date" when every calendar day counts — a hotel stay counted in days, an event that runs from the first to the last day, or a work schedule.
How months and years are added
Adding months keeps the same day of the month: 15 March plus one month is 15 April. If that day does not exist in the target month, the last day of the month is used, so 31 January plus one month is 28 February (29 in a leap year). Adding a year to 29 February gives 28 February in a common year.
Weekdays and business days
The weekday count includes Monday to Friday within the counted days. Public holidays differ by country and region, so they are not removed — subtract them yourself if you need exact business days.
Frequently asked questions
How many days until a date?
Put today as the start date and the target as the end date, with "include the end date" unticked. The result is the number of days left.
How do Korea, Japan and China count legal deadlines?
Their civil codes all follow the same rule: when a period is set in days, weeks, months or years, the first day is not counted unless the period starts at midnight. Our Korean, Japanese and Chinese pages explain this with the relevant article.
Are my dates sent anywhere?
No. All calculations run in your browser.
Related tools
- Age Calculator — exact age in years, months and days, plus Korean age