Pick two dates and this works out exactly how much time sits between them — as calendar years, months and days, and as a plain count of days and weeks. It starts on today’s date, so usually you only need to fill in the second field.
Key terms
- Days between — counts the gaps, not the dates. From the 1st to the 3rd is 2 days.
- Include both days — counts the dates themselves. From the 1st to the 3rd becomes 3 days.
- Calendar difference — the result expressed as years, months and days, following the actual calendar rather than assuming every month is the same length.
How it works
The total number of days is straightforward: both dates are treated as points on a timeline and one is subtracted from the other. Everything is handled in UTC, so a clock change in spring or autumn cannot turn a day into 23 or 25 hours and push the answer out by one.
The calendar breakdown is the harder half, because months are not a fixed length. The calculator counts whole months first, then measures the days left over.
Calendar difference
whole months, then the days remaining after adding those months to the start date
Adding a month clamps to the end of the target month: 31 January plus one month is 28 February, not 3 March.
That clamping rule is what makes awkward pairs come out sensibly. From 31 January to 1 March is reported as 1 month and 1 day — because one month after 31 January is the end of February, and one day after that is 1 March. Subtracting the numbers directly would produce a negative number of days and a confusing answer.
Which counting method do you want?
It depends entirely on what you are counting, and the two answers always differ by one.
- Days between suits durations: nights in a hotel, days of interest, notice periods.
- Include both days suits occupancy: days of leave taken, days a festival runs, days a member of staff was present.
A conference from the 10th to the 12th is 2 days between and 3 days inclusive. Neither is wrong; they answer different questions.
How to use this calculator
- The From field starts on today. Change it if you need a different starting point.
- Pick the To date. The result appears as soon as both dates are set.
- Switch the counting method if you need the inclusive answer.
- If you enter the dates the wrong way round, the calculator measures from the earlier one and says so rather than showing a negative span.
Frequently asked questions
Are leap years included?
Yes. 29 February is a real date in the count, so a span crossing a leap day is one day longer than the same span in an ordinary year. From 28 February to 1 March is 2 days in 2024 and 1 day in 2025.
Why does the years-and-months answer not match days ÷ 365?
Because months and years are not all the same length. The calendar breakdown follows the real calendar; dividing days by 365 assumes an average year and will disagree with it, particularly over long spans.
Does this count working days?
No — every day is counted, including weekends and public holidays. Working-day counts depend on which country and sometimes which region you are in, which is a different calculation.
Can I use dates far in the past or future?
Yes, within the range the date control accepts. Be aware that dates before the Gregorian calendar was adopted locally are historically ambiguous — countries switched in different years, so a date in the 1700s may not mean what a modern calendar suggests.
What happens if I put the later date first?
The calculator swaps them, gives you the length of the span, and adds a note saying it did. A negative number of days is almost never the answer anyone wants.
