Date & Time
Age, duration & timezone calculators
Days Between Dates Calculator
Count the exact number of days between two dates — for deadlines, contracts, projects, leave and anniversaries. Enter a start date and an end date and the calculator shows the total days, the count in weeks, and a calendar year/month/day breakdown. Counting exclusive of the end date, 1 January 2026 to 31 January 2026 is 30 days; counting inclusive of both endpoints it is 31 days — the tool shows both and lets you toggle the convention, because that one-day gap is the most common off-by-one error. All the math runs on UTC midnights so a day is always a full calendar day, even across a daylight-saving change, and everything is computed in your browser. If you enter the dates in the wrong order the result is order-normalized to a positive count, so you never see a negative number.
Total days = floor((end − start) / 86,400,000 ms) on UTC midnights
- 1 Jan 2026 → 31 Jan 2026 = 30 days (exclusive) or 31 days (inclusive of both)
- Also shown: weeks and a calendar year/month/day breakdown
Frequently asked questions
How many days are between two dates?
Subtract the start date from the end date. Counting exclusive of the end date, 1 January 2026 to 31 January 2026 is 30 days; counting inclusive of both endpoints it is 31 days. This tool shows both figures plus the difference in weeks and a year/month/day breakdown.
Should I count both the start and end date?
It depends on the convention you need. Exclusive counting (nights between) gives 30 for Jan 1 to Jan 31; inclusive counting (both endpoints) gives 31. The calculator exposes an explicit toggle and labels each result so you can pick the one your deadline uses.