Date Calculator | Add or Subtract Days, Weeks, Months

Q: How does this date add and subtract calculator work?

Enter a start date , choose whether to work in mixed units or a single unit, then enter the amount to add or subtract. The calculator returns the resulting calendar date.

Q: Can I add and subtract days, weeks, months, and years?

Yes. You can use mixed date units like years , months , and days together, or switch to a single total in days , weeks , months , or years .

Q: Can I subtract dates with this calculator?

Yes. Enter negative values such as -7 days or -1 month to move backward from the start date.

Q: Why can adding months give different day counts?

Calendar months do not all have the same length. Adding 1 month means moving to the same calendar day in the next month when possible, not simply adding a fixed number of days.

Q: What is the difference between adding days and adding weeks?

Adding 1 week is the same as adding 7 days . The separate week input is mainly a convenience when the date shift is expressed in full weeks.

Date Calculator: add or subtract days, weeks, months, or years from any date to get the resulting date.

Use this date add and subtract calculator to add or subtract days, weeks, months, or years from any start date and get the resulting calendar date.

You can work with mixed date offsets such as 1 year, 2 months, and 10 days, or switch to a single-unit mode like total days or total weeks. It is useful for deadlines, contracts, shipping estimates, scheduling, renewals, and planning future or past dates.

Initial Data

Start date

day	month	year

End date

day	month	year

Result

Weekdays

Start date: -
End date: -

Time between dates:

- years
- months
- days

Time between dates in different units:

- seconds
- minutes
- hours
- days*
0.00 weeks
- months
- years

* 1.00 Days (including start date)

Date Add And Subtract FAQ

How does this date add and subtract calculator work?
Enter a start date, choose whether to work in mixed units or a single unit, then enter the amount to add or subtract. The calculator returns the resulting calendar date.

Can I add and subtract days, weeks, months, and years?
Yes. You can use mixed date units like years, months, and days together, or switch to a single total in days, weeks, months, or years.

Can I subtract dates with this calculator?
Yes. Enter negative values such as -7 days or -1 month to move backward from the start date.

Why can adding months give different day counts?
Calendar months do not all have the same length. Adding 1 month means moving to the same calendar day in the next month when possible, not simply adding a fixed number of days.

Can I use this for deadlines and due dates?
Yes. This calculator is useful for estimating deadlines, delivery dates, billing cycles, contract periods, renewals, and other schedule-based date calculations.

What is the difference between adding days and adding weeks?
Adding 1 week is the same as adding 7 days. The separate week input is mainly a convenience when the date shift is expressed in full weeks.

» Date Calculator: Add or subtract