Add or subtract days from a date
Date display order follows your browser or device locale.
Days are added or subtracted as calendar days using UTC internally to avoid daylight-saving shifts.
Add or subtract calendar days
Enter a reference date, choose the number of days, then choose Add or Subtract. The calculation moves by calendar days, so weekends and public holidays count like any other day.
Worked example
Starting from 18 August 2026, adding 45 calendar days gives 2 October 2026. Subtracting 45 calendar days gives 4 July 2026.
Leap years are included automatically
If the interval crosses 29 February in a leap year, that date is counted normally. This is safer than converting months or years into a fixed number of days.
Not a business-day calculator
This tool does not remove Saturdays, Sundays or holidays. A deadline based on working days also requires the holiday calendar that applies to the relevant country or organisation.