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Date & Time

Date Add or Subtract Calculator

Add or subtract days, weeks, months or years from a date.

Enter your values

Enter the start date in YYYY-MM-DD.

Enter the amount you are working with.

Choose one of: Days, Weeks, Months, Years.

Choose one of: After (add), Before (subtract).

Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.

Results
Resulting date
2026-10-26
Written out
Mon, 26 Oct 2026
Day of the week
Monday
Days from start
90

Quick answer

Adding days shifts the calendar directly; adding months keeps the day-of-month where the target month is long enough.

At a glance

What it doesAdd or subtract days, weeks, months or years from a date.
CategoryDate & Time
Inputs neededStart date, Amount, Unit, Direction
Main outputResulting date
CostFree — no sign-up, no download

How to use the Date Add or Subtract Calculator

  1. 1Enter the starting date.
  2. 2Enter how much time to shift.
  3. 3Choose the unit and direction.

Inputs explained

Start date(YYYY-MM-DD)
Enter the start date in YYYY-MM-DD.
Amount
Enter the amount you are working with.
Unit
Choose one of: Days, Weeks, Months, Years.
Direction
Choose one of: After (add), Before (subtract).

Worked example

Using the values the calculator loads with:

Inputs

  • Start date2026-07-28 YYYY-MM-DD
  • Amount90
  • UnitDays
  • DirectionAfter (add)

Results

  • Resulting date2026-10-26
  • Written outMon, 26 Oct 2026
  • Day of the weekMonday
  • Days from start90

Frequently asked questions

What is 90 days from today?

Enter today's date with 90 days added — useful for contract notice periods and return windows.

What happens on 31 January plus one month?

It clamps into the next month, giving 2 or 3 March, because February has no 31st.

What do I need to enter into the Date Add or Subtract Calculator?

Just 4 values: start date, amount, unit, direction. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.

How does the Date Add or Subtract Calculator work out the answer?

Adding days shifts the calendar directly; adding months keeps the day-of-month where the target month is long enough. The working is shown step by step so you can verify the result by hand.

Is the Date Add or Subtract Calculator free, and do I need an account?

It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.

Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.