Add or Subtract Days from a Date
Add or subtract days from a date to find a due date, deadline or expiry. Handles month ends and leap years, and accepts negative day counts to go back.
What is the Add or Subtract Days from a Date?
Need to know the date 90 days from today, when a 45-day notice period ends, or which date was 30 days before a payment? This tool adds or subtracts a number of days from any starting date and shows the resulting date. Month ends, year changes and leap days are handled as real calendar dates, so you never have to count on your fingers across February or December.
Use a positive number to move forward and a negative number to go back. The count must be a whole number of days, and the result is shown in YYYY-MM-DD format. Every day is counted, including weekends and holidays; the tool does not skip non-working days or add months as units. Everything runs in your browser and works the same in any time zone.
How to use the Add or Subtract Days from a Date
- Check the Starting date field, which is filled with today's date automatically, and change it if you are counting from another day (YYYY-MM-DD).
- Type the number of days in Days to add (negative to subtract), for example 90 or -30.
- Press Calculate to see the resulting date.
- Copy the result for your calendar or document.
- Press Reset to clear the fields and try another date.
Features
- Add or subtract whole days with one field, starting from today by default
- Handles month lengths, year changes and leap years
- Result shown as a YYYY-MM-DD date
- Accepts day offsets up to ±3,000,000
- Errors for fractional days or results outside the years 1000–9999
Why use this add or subtract days from a date
- Work out deadlines, due dates and expiry dates
- Plan notice periods and follow-ups
- Find a past date for records or claims
- Quick, private and works on mobile
Formula used
Result = starting UTC calendar date + signed whole-day offset.
Examples
90 days from a date
Input: Starting date: 2026-10-30, Days to add: 90
Result: 2027-01-28 Counting 90 calendar days forward crosses into the new year.
Across a leap day
Input: Starting date: 2024-02-28, Days to add: 2
Result: 2024-03-01 2024 has 29 February, so two days later is 1 March.
Going back one day
Input: Starting date: 2026-03-01, Days to add: -1
Result: 2026-02-28 2026 is not a leap year, so the day before 1 March is 28 February.
Results are estimates for general information, not financial, medical, legal, tax, or property advice. Confirm important figures with the relevant institution or a qualified professional.
Add or Subtract Days from a Date: frequently asked questions
How do I subtract days from a date?
Enter a negative number in the Days to add (negative to subtract) field. For example, a starting date of 2026-03-01 with -1 gives 2026-02-28. There is no separate subtract button; the minus sign tells the tool to count backwards through the calendar.
Does the tool skip weekends and public holidays?
No. It counts every calendar day, including Saturdays, Sundays and holidays. If your deadline is defined in working days or business days, such as some bank or court timelines, you will need to adjust the result yourself or check against a holiday calendar.
Is the starting date counted as day one?
No. Adding 1 day gives the next date, and adding 0 returns the starting date unchanged. If a rule says a period includes the first day, such as a 30-day window starting today, subtract one from the number you enter to get the last day of that window.
Can I add months or years instead of days?
Not directly. The field accepts days only, because months have different lengths. To approximate, convert to days yourself, for example 365 or 366 for a year. If you need an exact same-day-next-month result, check the calendar, since adding 30 or 31 days will not always land on the same date.
Why do I see an error?
The day count must be a whole number between -3,000,000 and 3,000,000, so 1.5 is rejected. The starting date must be a real date in YYYY-MM-DD format, and the result must fall between the years 1000 and 9999. Fix the highlighted field and press Calculate again.