Days between dates, without the off-by-one headache
Three date tools in one place: count the days between two dates, add or subtract time from a date, and count business days. Every calculation runs on UTC calendar days, so your time zone and daylight saving time can never push a result into the wrong day.
Weekday and weekend tallies cover the same span as the day count: starting with the start date, one day at a time, up to the end date (plus the end date itself when inclusive counting is on). Order does not matter — swapping the dates gives the same counts.
Need the dedicated pages? Add days to a date and subtract days from a date each give one direction the full page.
The dedicated business days calculator explains the convention and the holiday caveat in full.
The short answer, with a worked example
The days between two dates is simply end date − start date, counted in whole calendar days. From Sunday, 11 October 2026 to Friday, 25 December 2026 that is 75 days — 10 weeks and 5 days, or 2 months and 14 days. Of those 75 days, 54 fall Monday to Friday and 21 fall on a weekend. Tick "count the end date too" and the same span reads 76 days, because both the first and the last day are being counted as part of the period.
Leap days are handled by the calendar itself: 28 February 2024 to 1 March 2024 is 2 days, not 1, because 29 February 2024 sits in between. The same February span in 2026 is 1 day. Every result on this page is computed from real calendar dates in UTC — never from a 30.44-day "average month" — so a leap day inside your span is always counted.
Eight ways people use these three tools
Project deadlines
"Ninety days from signing" is a date, not a vibe. Add the term to the signing date and you have the deadline and its weekday — if it lands on a Sunday, you will see it before your client does.
Leave & notice periods
Count business days inside a notice period or between a resignation and a last working day, then subtract your company's public holidays by hand.
Countdowns that matter
Days until a wedding, an exam, a visa expiry or a contract renewal — the same subtraction, with the weekday of the big day attached.
Double-checking spreadsheets
Excel and Sheets subtract dates the same way this page does. If a sheet disagrees, it is usually counting both endpoints — the inclusive toggle reproduces that number so you can spot the difference.
Questions, answered
Do you count the first or the last day?
By default, neither the wording nor the math is ambiguous here: the result is the number of days that pass after the start day, which is the same as subtracting the two dates. The start day is day zero. If your situation counts both endpoints — a three-day rental "from the 1st to the 3rd" — turn on the inclusive option and the answer grows by exactly one.
Why doesn't the business-day count remove public holidays?
Because there is no single list to remove. A federal holiday in the US is a normal Tuesday in Canada; regional holidays differ inside the same country. Rather than bake in one country's calendar and quietly give wrong answers to everyone else, this tool counts weekdays only and says so. Pro, when it launches, will add per-country holiday calendars as an explicit choice.
Can daylight saving time change the answer?
Not here. All dates are converted to UTC midnights and subtracted as whole days. A 23-hour spring-forward day and a 25-hour fall-back day each count as exactly one calendar day, which is what contracts and calendars mean.
What about very long spans?
The tools accept any year the date picker allows and the arithmetic is exact across centuries — leap-year rules (including the century rule: 2000 was a leap year, 1900 was not) are handled by the calendar math underneath.