Counting the days between two dates
In "days between" mode the calculator subtracts the start date from the end date. By default the start day isn't counted and the end day is, which is how most people count: from Monday to Friday is 4 days. The result also shows the count with both dates included, which is what you want when counting an event that runs over several days, for example a hotel stay counted in days rather than nights.
Adding months and years
Adding days and weeks is simple arithmetic. Months are trickier because they have different lengths. If you add one month to 31 January, there is no 31 February, so the calculator moves to the last day of February (28 February, or 29 in a leap year). Adding a year to 29 February gives 28 February. This "end of month" rule matches how most contracts and banks handle it.
Worked examples
- From 15 October 2026 to Christmas Day 2026 is 71 days.
- 100 days after 15 October 2026 is Saturday 23 January 2027.
- One month after 31 January 2027 is 28 February 2027.
Common uses
Work out a 90-day deadline, the date 6 weeks from today, how long until a holiday or exam, a pregnancy due date in weeks, or the end of a 12-month contract. For UK notice periods or delivery times that skip weekends and bank holidays, use the working days calculator. Everything is worked out in your browser.
Frequently asked questions
How many days until Christmas 2026?
From 15 October 2026 there are 71 days until 25 December 2026. Change the start date to count from any day.
What date is 90 days from today?
Choose "Add / subtract", enter 90 days and the result shows the exact date and weekday.
Does the count include the start date?
The main figure doesn’t count the start day. The "including both dates" line adds one.
✨ New: Remove the background from any image free – private, in your browser, transparent PNG.
Related free tools
Sources
Note: This free tool runs entirely in your browser. No data is sent or stored. Results are for information only.