Add calendar days
Calendar days include weekends and holidays.
Add, subtract or compare calendar dates.
Answer queries such as “451 calendar days from September 18, 2026,” “116 days before September 16, 2026,” or “how many days between two dates.”
Subtract calendar days
Uses straightforward Gregorian calendar-day subtraction.
Measure the gap
Shows the standard exclusive endpoint difference plus the inclusive count.
Common date calculations
For a days-from calculation, September 18, 2026 plus 30 calendar days is October 18, 2026. For a days-before calculation, October 27, 2026 minus 30 calendar days is September 27, 2026. Neither calculation counts its starting date as day 1.
When should I use each tool?
Choose days from to move forward toward a deadline, days before to work backward from an event, and days between to compare two dates without changing either one. All three include weekends and public holidays. Business-day calculations require a country and holiday calendar and are not provided here.
What about leap years and clock changes?
February 29 is counted when the relevant date range includes it; for example, one calendar day from February 28, 2028 is February 29, 2028. Moving by calendar dates is different from adding a fixed number of 24-hour periods, particularly when clocks change for daylight saving.
Use any practical calendar-day offset.
The calculator can handle offsets from 0 to 10,000 days. Dedicated result pages provide the same calculation method, calendar context and nearby-date navigation.