📅 Date Difference Calculator — How Many Days Between Dates?
← Math & EverydayTwo dates, one question: how much time is really between them? Count the days, see the weeks and months, and find out how many weekdays are hiding in the middle — even when a leap year gets involved.
Your date difference
Pick two dates to see the difference.
Some days are closer than they look
A date on a calendar feels simple until you have to count to it. Is a weekend included in a deadline? Does a month mean 30 days, or the whole stretch from 31 January to 28 February? And why does a week-long trip sometimes include eight calendar dates?
This calculator takes the guesswork out of those little questions. Choose two dates and it shows the days between them, the calendar years and months, and how many Mondays through Fridays are in the mix. You can also switch on inclusive counting when you want the first and last dates to count.
It is handy for planning a holiday, checking a project timeline, counting down to something exciting, or settling a surprisingly heated argument about whether the first day counts. The useful bit isn't just the answer — it's seeing which counting rule gave you that answer.
The calendar has a few tricks up its sleeve
Seven days apart. Eight dates on your itinerary.
Pick a Monday and the Monday after it. There are 7 elapsed days between them, but 8 calendar dates if you count both Mondays. It's not a trick: one method measures the gap, and the other counts the labels on the calendar.
Friday to Monday: three days, one weekday.
From Friday to the following Monday is 3 calendar days. Under this calculator's default rule (after Friday, through Monday), there's only 1 Monday–Friday date in that span. The other two are Saturday and Sunday. Your calendar has been working all weekend; your weekday count hasn't.
The same two dates can be one day or two.
From 28 February to 1 March is 1 day in 2023 and 2 days in 2024. Same month names, same day numbers — but the leap day sneaks a whole extra square into the calendar.
One calendar month doesn't always mean thirty days.
From 31 January to 28 February 2023 is 28 days, but this calculator also counts it as 1 calendar month because the month-end date is clamped to February's last day. A calendar month is a position on the page, not a fixed pile of days.
Jump exactly 7 days and the weekday stays put.
Any two dates exactly seven days apart share the same weekday. Jump 14, 21 or 70 days, and that's still true. It's the easiest calendar party trick to check with this calculator — no memory of month lengths required.
How does this date difference calculator work?
Calendar arithmetic counts actual dates, not a shortcut like “every month is 30 days”. The calculator converts each date into its place on the Gregorian calendar, finds the exact gap, then breaks that gap into the units you've asked to see.
Elapsed calendar days
Days between dates = later calendar-day number − earlier calendar-day number
For example, 12 October 2026 − 5 October 2026 = 7 elapsed days. Each date is turned into a whole day number in the calendar, so a local clock changing for daylight saving cannot add or remove a day. Two dates are always the same distance apart, whichever time zone the page is read in.
Counting both dates
Counted dates = elapsed days + 1 (when both dates are counted)
The default counts the dates after the earlier date up to and including the later one, which is why 5 October to 12 October is 7 days. With both dates counted the interval becomes the 8 calendar dates from 5 October through 12 October. Same two dates, one different rule — and the weekday counts follow whichever rule is on.
Complete weeks and leftover days
Complete weeks = floor(counted dates ÷ 7)
Leftover days = counted dates mod 7
Thirty counted days is 4 weeks and 2 days. With both dates counted, the same span is 31 dates, or 4 weeks and 3 days. A complete week here means seven counted dates — not a Monday-to-Sunday week on a printed calendar.
Calendar years, months and days
Anchor = the earlier date, moved forward by whole calendar months
Days left = later date − anchor
The month count is the largest whole number of months that still lands on or before the later date, with the day kept where possible and clamped to the month's last day where it isn't. So 31 January to 28 February 2023 is 1 month and 0 days, and 15 January to 11 October 2026 is 8 months and 26 days.
Months don't have a fixed length. This calculator counts complete calendar months and then leftover days. If a month doesn't have your starting day (like 31 February), it uses that month's last day. Other calculators can choose a different month-end convention, so month/day breakdowns may differ even when the total number of days agrees.
This breakdown describes the distance between the two dates, so ticking Count both dates does not change it.
Weekdays and weekends
Weekdays are Monday to Friday; weekends are Saturday and Sunday. For a range of n counted dates, every whole seven-day block contains exactly one of each weekday, and the remaining few days are dealt out from the first counted date. That makes the count instant even across centuries, and it guarantees the seven bars add up to the counted dates.
Public holidays are not removed. This is a weekday count, not a holiday-adjusted business-day count, and not every country works a Monday-to-Friday week.
The quarter points on the timeline
Each marker is the earlier date plus a quarter, a half or three quarters of the elapsed days, rounded to a whole day. The dates are calendar positions, not precise instants: the halfway marker is a date, not the exact middle of a number of hours. Because the markers use the elapsed span, ticking Count both dates never moves them.
A few things to know
- Dates are counted using the Gregorian calendar, including its leap-year rules.
- Results are based on calendar dates, not clock times. Time zones and daylight-saving changes won't add or remove a date from the gap.
- Weekdays mean Monday to Friday. Public holidays, school holidays, rostered days off and local working-week customs are not deducted.
- Inclusive counting adds the first date to the selected range. It does not add a full extra elapsed 24 hours between endpoints.
- Calendar months and years have different lengths, so a month/year breakdown can differ from a simple day total divided by 30 or 365.
- Official deadlines, legal notices, contracts and visa requirements may count days differently. Follow the rule that applies to your situation.
- Selected dates are processed on this device and are not sent anywhere; the calculation runs entirely in the browser.
Frequently asked questions
How do I calculate the number of days between two dates?
Choose a start and end date. The calculator counts the calendar-day boundaries between them, so dates one day apart return one elapsed day. It also converts that result into weeks and days, shows the calendar months and years, and counts weekdays and weekends separately.
Does this calculator include the start and end dates?
Not by default. The standard result measures the elapsed days between the dates. Turn on Count both dates to include the starting date as well as the ending date. For example, Monday to the following Monday is 7 days apart but covers 8 calendar dates when both Mondays count.
How many working days are between my dates?
The weekday count shows Monday to Friday dates in your selected range. It doesn't subtract public holidays, annual leave or rostered days off, so it's best described as weekdays, not a guaranteed number of workdays. Check local holiday and deadline rules if you need an official business-day count.
Does it include weekends?
Yes. The headline calendar-day result includes Saturdays and Sundays. A separate result shows the Monday–Friday dates and Saturday–Sunday dates so you can see the split. The inclusion checkbox applies to both sets of counts in the same way.
What happens when my dates include a leap year?
Leap days are counted automatically. For example, from 28 February to 1 March is two days in 2024 because 29 February sits in between, but one day in 2023. You don't need to switch on a special leap-year setting.
Why can the calendar month result differ from the total days?
Months don't all have the same number of days. This calculator counts complete calendar months first, using the last day of a shorter month when necessary, then counts the leftover days. That means 31 January to 28 February 2023 can be one calendar month even though only 28 days have elapsed.
Can I enter an end date before the start date?
Yes. The calculator shows the absolute length of the gap and tells you that the dates are in reverse order. Its weekday and weekend counts use the chronologically earlier and later dates, and the Swap dates button lets you flip the inputs without retyping them.
Is the result affected by time zones or daylight saving?
No. This tool compares calendar dates, not exact clock-time instants. A date is counted as one calendar day even when a local clock moves forward or backward for daylight saving. For a calculation involving precise hours or time zones, you need a date-and-time tool instead.
Is a week always seven days here?
Yes. A complete week means seven counted calendar dates, plus any leftover days. It doesn't mean a Monday-to-Sunday week on a printed calendar, and it doesn't change when a public holiday occurs.
Can I use it to calculate a legal or official deadline?
It's useful for checking a basic calendar-day span, but don't rely on it as the final authority for legal, regulatory, immigration or contractual deadlines. Those rules can have different start/end counting methods, business-day definitions, local public holidays and cut-off times.
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