Date calculator: add or subtract days
Pick a date, then add or subtract a length of time. Or choose “Difference” to compare two dates.
Result
Monday, January 18, 2027New date
- Gap in days
- 100
Inputs
- What do you want to do?
- Add
- Start date
- 2026-10-10
- How many?
- 100
- Unit
- Days
How it is calculated
Days and weeks: we move through the calendar day by day.
Result
New date
- Gap in days
- 100
How it is calculated
- Days and weeks: we move through the calendar day by day.
- Months and years: we change the month and keep the same day if it exists.
- If the day does not exist (31 April…), we use the last day of the month.
- Difference: we count the days between the two dates, without the last day unless you ask.
Example
10 October 2026 + 100 days = Monday 18 January 2027.
Good to know
- Gregorian calendar.
- Public holidays and weekends are not removed.
Frequently asked questions
What is this tool used for?
Pick a date, then add or subtract a length of time. Or choose “Difference” to compare two dates.
How is the result calculated?
Days and weeks: we move through the calendar day by day.
What should I check before using the result?
Gregorian calendar.