Date Add and Subtract Calculator
Move a calendar date forward or backward by days, weeks, months, or years using UTC date arithmetic.
Loading tool…
How to use Date Add and Subtract Calculator
Days and weeks advance calendar boundaries. Months and years retain the day where possible and clamp to the last day of the target month when necessary.
- Enter starting date, signed amount (negative subtracts).
- Check the selected calculation options and input units.
- Run the calculator, review the result, then copy or download it.
Good to know
- Whole signed offsets up to 1 million. Dates and results must be in years 0001–9999. UTC calendar arithmetic ignores time zones and daylight-saving clock changes.
- Calendar dates are processed locally in UTC with Gregorian leap-year rules. No user input or calculated dates are saved by the tool.
Common questions
What calculation does Date Add and Subtract Calculator perform?
Days and weeks advance calendar boundaries. Months and years retain the day where possible and clamp to the last day of the target month when necessary.
What is one month after January 31?
It is the last day of February: February 28, or February 29 in a leap year. This clamp rule is explicit rather than rolling into March.
Keep going with related tools
All date & time →Date Difference Calculator
Count signed calendar days between two dates and break the absolute interval into weeks and days.
CalculatorsAge Calculator
Find completed years, total calendar days lived, and the next birthday from two dates.
CalculatorsDeclared Unit Vesting Schedule
Build a monthly unit-release schedule from your grant, cliff and original-day calendar convention.
EducationHistorical SM-2 Review Schedule Workbench
Apply an explicit historical SM-2 transition to local card-state records and preserve the previous state.
CalculatorsProject Critical Path Planner
Calculate earliest and latest task timing, exact total slack and critical connections in a task network.
Date & timeRetail Fiscal Calendar Calculator
Map a date to a user-anchored retail fiscal week and period, and download the complete week calendar.