Add / Subtract Days from a Date
Add or subtract days, weeks, months or years to a date and see which weekday the result falls on.
Date & TimeResult
Enter your values and calculate; the result will show up here.
How is it calculated?
Pick a start date, then enter how much to add or subtract and in which unit. Months and years follow the calendar; if the day doesn't exist in the target month (31 January + 1 month) it lands on the last day of that month.
Formula
Result = Start ± (amount × unit) 31 Jan + 1 month = 28 Feb (29 Feb in a leap year)
Example
Start date: January 15, 2025 · Operation: Add · Amount: 45 · Unit: Days → Resulting date: March 1, 2025
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Frequently asked questions
What is 31 January plus one month?
February has no 31st, so the result is the last day of February: the 28th, or the 29th in a leap year.
Can I add working days?
This tool adds calendar days. To count working days between two dates, use the Days Between Dates calculator.