Date & Time Calculators
Date Calculator
Add or subtract days, weeks, months or years from any date to find the exact resulting date and weekday.
About the Date Calculator
A date calculator is handy whenever you need to project a date forward or backward — a delivery date 45 days out, a subscription that renews in 6 months, or a deadline 90 days from today.
Just choose a starting date, pick add or subtract, enter the amount and unit, and the calculator returns the exact date along with the day of the week.
How to use the Date Calculator
- Pick a start date.
- Choose Add or Subtract.
- Enter the amount and select the unit (days, weeks, months or years).
- Click Calculate Date.
How the calculation works
Result Date = Start Date ± (Amount × Unit)
Month and year additions respect calendar boundaries, so adding one month to 31 January rolls correctly into the following months.
Example
Start date 1 March 2026, add 90 days → the result is 30 May 2026, a Saturday.
Frequently asked questions
Add or subtract any number of days, weeks, months or years from a chosen date to find the resulting calendar date.
Months advance the calendar month while keeping the day where possible, adjusting automatically for shorter months.
Yes, the result includes the full day of the week for the calculated date.
Yes, choose the Subtract option to move the date into the past.