Find the number of days between two dates, or add and subtract days from a date. Runs in the page.
Find the days between two dates, or shift a date by a number of days.
What the date calculator does
Work out the number of days between two dates, or add and subtract days from a date. It is useful for deadlines, trips and age-from-a-date style maths.
Frequently asked questions
Does it count the start day?
The difference is a simple calendar-day count between the two dates, matching how most people estimate gaps.
Does it handle time zones?
It works on plain calendar dates, so it is unaffected by time zones.
Is anything uploaded?
No. The maths runs in the page.
How to use it
- Enter the start date in the first field using a standard format such as 15/03/2025 or 2025-03-15, depending on the format supported on the page.
- Enter the end date or the date you want to shift from in the second field, using the same format you used for the first date.
- Select whether you want to find the difference between the two dates or add or subtract a number of days, then enter the number of days in the provided box if performing an addition or subtraction.
- Press the calculate button to see the result displayed immediately below the controls, showing the total day count or the resulting shifted date.
Where it comes in handy
A project manager needs to confirm that a deliverable due on 12 June 2025 is exactly 87 working days after a kick-off on 15 March 2025. The calculator returns the raw day count so the schedule can be checked against a 90-day contract window without manual counting.
A traveller booked a hotel stay from 4 August 2025 to 18 August 2025 and wants to know the total nights at a rate of 85 pounds per night. The calculator shows 14 days, which multiplied by 85 gives a total of 1,190 pounds before taxes.
A student started a course on 10 September 2024 and needs to verify that 130 days have passed by the mid-term assessment on 18 January 2025. The result confirms the gap so the instructor can validate attendance eligibility.
Worth knowing
- The day difference is a simple calendar count and does not adjust for public holidays, weekends, or business-only periods.
- When adding or subtracting days across month boundaries, the tool handles rollovers automatically, but crossing a leap year such as 2024 will include 29 February in the count.
- The result uses plain integer days with no fractional part; partial days are not calculated and no time-of-day information is considered.