Date Difference Calculator
Find the number of days between two dates — for a countdown to a future date or the gap since a past one.
How it's calculated
The total day count is a straightforward difference between the two calendar dates. The years/months/days breakdown borrows from the next larger unit when a subtraction goes negative — the same way you'd work it out on paper — so it stays accurate across different month lengths and leap years.
Worked example
From 15 January 2024 to 1 March 2024 is 46 days, which is 6.6 weeks and shows as a breakdown of 0 years, 1 month and 15 days. Over a whole year the answer depends on leap years: 28 February 2023 to 28 February 2024 is 365 days, but 28 February 2024 to 28 February 2025 is 366, since 29 February 2024 falls in between. Both show as 1 year, 0 months and 0 days.
Counting the end date too
The result is the number of days elapsed between the two dates. If you want to count both the first and the last day, as for a hotel stay or a course, add one: the January to March example becomes 47 days.
What it doesn't do
It works on calendar dates only, so there are no times of day, and daylight-saving changes cannot shift the count. It also doesn't skip weekends or public holidays, so it can't give working days.
Common uses
- Counting down the days to an event, deadline, or trip
- Working out how long ago something happened
- Checking the length of a stay, lease, or project timeline
Frequently asked questions
Does it matter which date I enter first?
No — the calculator works out the gap either way round, so you can enter today's date and a future date, or two past dates, in any order.
Does this count the start or end day?
The total day count is the difference between the two calendar dates (an exclusive count of full days elapsed), which matches how 'days until' countdowns are typically expressed.