Free Online Date Difference Calculator, Days, Weeks, Months & Years
Count exactly how long there is between two dates. The answer comes as total days, and also broken into years, months and days, plus weeks and working days. Leap years and month lengths are handled properly, so the number does not drift by a day the way rough methods do.
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📅 Date DifferenceDays, weeks, months and working days · both counting methods
Every date is worked out in your browser. Nothing you type is sent anywhere.
📅 The two dates
Counting
A hotel from Monday to Friday is four nights and five days. Notice periods and
prison sentences count days; interest and hotel bills count nights.
Try one of these
Nights between
—
The same gap, in every unit
Unit
Amount
How it was worked out
Date ranges you come back to, saved in this browser only.
No saved setups yetOn the Difference tab, press Save setup to keep what you are working with.
Recent date ranges, kept in this browser only.
Nothing here yetPress Log to history on the Difference tab to keep an answer here. Load one back with the arrow button.
When
What was worked out
Actions
How dates are shown
The format only changes what you read. Every date you type into a date box is handled as
year, month and day, so 02/09 can never be mistaken for the second of September in one
place and the ninth of February in another.
Display
Size
Theme
Full screen hides the page around the tool. Press Escape, or the button in the bar, to
come back.
History
Save history
Your data
Settings, history and saved setups live in this browser and nowhere else. There is no
account and no server, which also means clearing them here is final.
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Both answers are right. They are answers to different questions.
Count the fence posts and you get eight. Count the gaps between them and you get seven. A date
range is exactly the same shape, and which number you want depends entirely on what you are
counting: a hotel charges for the nights, a notice period counts the days, and a
sentence of eight days served from the 1st ends on the 8th, not the 9th.
What you are counting
1st to 8th
Why
Hotel nights
7
you sleep there on the 1st through the 7th, and leave on the 8th
Interest on a loan
7
interest accrues for whole days that have passed
Days of leave taken
8
you are away on the 8th as well, so it counts
A notice period
8
usually inclusive of both ends, but read the contract
Age, and time until an event
7
nothing has happened yet on the day you start counting
Most date calculators pick one and never say which. That is the whole reason the
switch above exists. The answer you did not pick is printed underneath the one you did,
so the difference is never a surprise.
Contracts and courts have their own rules, and they win. Many legal systems say
the first day is not counted and the last one is. If money or a deadline turns on the
answer, the wording of the document decides it, not this page.
Why the Months Answer Is Never Quite Exact
A month is not a length. It is a name for a box of variable size.
Days are all the same size, so the days answer is a plain fact. Months are not: they run from 28
to 31 days, so "two months" is somewhere between 59 and 62 days depending on which two. That is
why the big number here is days, and the years, months and days breakdown sits underneath
it as a second reading rather than the headline.
The gap
In days
Reads as
1 Jan to 1 Mar 2026
59
2 months
1 Jul to 1 Sep 2026
62
2 months
31 Jan to 28 Feb 2026
28
28 days, not 1 month
29 Feb 2024 to 28 Feb 2025
365
11 months and 30 days
The breakdown counts whole years first, then whole months, then the days left over.
When the day of the month runs short it borrows from the month before the end date. That is
the ordinary way people count on paper, and it is written here because the other reasonable
method gives a different answer for the same pair of dates.
How to Use the Date Difference Calculator
Four steps, and the third one is the one that catches people.
1
Pick the two datesBoth boxes are proper date pickers, so 02/09 can never be read as the second of September in one place and the ninth of February in another. The day of the week, the day of the year and the week number appear under each one.
2
Choose how the days are countedNights between is the gap, the way a hotel or a lender counts. Both days counted adds the day you started on, the way leave and notice periods are counted. Whichever you pick, the other answer is printed underneath.
3
Read the days first, then the monthsDays are all the same size, so that number is a plain fact. Years and months are a second reading, because a month is anything from 28 to 31 days long.
4
Open the working if the number surprises youIt shows both dates as day numbers, the subtraction, whether one was added for the inclusive count, and how the years and months breakdown was arrived at.
What to Know Before You Start
Including the things this tool cannot do.
The last day is a choice, not a fact. From the 1st to the 8th is seven days or eight, and both are correct answers to different questions. The switch above decides which one is shown large, and the other one is always printed with it.
Months are not a fixed length. Two months is 59 days from January and 62 from July. The years and months breakdown is counted on the calendar rather than by dividing, which is why it can read 11 months and 30 days for a gap of exactly 365 days.
Time of day is not part of this. Everything here works on whole calendar dates. If you need hours and minutes between two moments, that is a different question and the hours calculator answers it.
Time zones are not part of this either. A date is treated as a date, not as a moment. Dates are handled as year, month and day and never turned into a local timestamp, which is exactly what stops a daylight saving change from quietly moving an answer by one day.
Working days here assume Saturday and Sunday. No public holidays are applied and the weekend cannot be changed on this page. If your week runs differently, or you have a list of holidays, the working days calculator handles both.
A contract beats a calculator. Notice periods, limitation periods and interest clauses all have their own counting rules, and many legal systems exclude the first day and include the last. Read the wording before relying on a number from any tool.
Key Features & Capabilities
What this tool does, and what it deliberately does not.
Both counting methodsNights between and both days counted, side by side on every answer rather than buried in a setting.
Every unit at onceDays, weeks, decimal weeks, months, years, hours, minutes, seconds, working days and weekend days.
Day, week and year factsEach date shows its weekday, its day number in the year and its ISO week number as you pick it.
The working shownDay numbers, the subtraction and the inclusive adjustment, so a surprising answer can be checked rather than trusted.
Nothing leaves the pageNo server, no account and no upload. Saved setups and history live in this browser and can be cleared from Settings.
Saved setups and historyKeep the date ranges you look at often and load one back with a single button.
About the Date Difference Calculator
A date difference calculator answers a question that sounds simple and has two correct answers. From the first of the month to the eighth is seven days if you are counting the gaps between them, and eight if you are counting the days themselves. Hotels and lenders count the first way. Leave, notice periods and sentences count the second. Nothing in the two dates tells you which one was meant, so this page asks, and then shows you both.
Underneath, everything runs on whole days. Each date is turned into a plain number of days counted from the first of January 1970, and the difference is a subtraction. That sounds like an implementation detail and it is the reason the answers are trustworthy: measuring the gap in milliseconds instead gives a wrong result twice a year, on the days when the clocks change and a day is 23 or 25 hours long. Rounding hides the error rather than fixing it.
The years and months breakdown is deliberately the second number rather than the first. Days are all the same size, so a count of days is a fact. A month is not a length, it is a label on a box that holds between 28 and 31 days, which is why two months can be 59 days or 62 depending on which two months they were. The breakdown counts whole years, then whole months, then whatever days are left, borrowing from the month before the end date when the day of the month falls short. Other reasonable methods exist and give different answers, so the method used here is written down rather than assumed.
Frequently Asked Questions
Everything worth knowing before you trust the answer.
Subtract one date from the other and you get the number of whole days that separate them. Whether you then add one depends on whether the last day should count. This page shows both, with the one you asked for in large type and the other underneath, so there is no guessing which convention it used.
It depends entirely on what you are counting. Nights in a hotel, days of interest and time remaining before an event all count the gaps, so the end date is not included. Days of leave, days of notice and days served all count the days themselves, so it is. If a contract or a court rule applies, that wording decides it.
Because calendar months are not all the same size. From the 29th of February 2024 to the 28th of February 2025 is exactly 365 days, but it is not a whole year on the calendar, since the 29th never arrives in 2025. The days figure is exact; the months figure is a description of the same gap in units that vary in length.
Yes, and not by adding a special case. Because every date is converted to a day number before anything is calculated, a leap day is simply a day that exists, in exactly the same way as any other. The 29th of February 2024 is accepted and the 29th of February 2026 is refused, because that date does not exist.
The answer panel and the table both show working days for a Monday to Friday week, with no public holidays applied. If you need a different weekend or a list of holidays taken out, the working days calculator on this site does both and shows which days it removed.
No, and that is a deliberate design decision rather than luck. Dates here are never turned into local timestamps, so the days on which clocks change are simply days like any other. Calculators that work in milliseconds can be one day out on those dates, and the error is invisible because rounding smooths it over.
Yes. The day numbering runs both ways from 1970, so earlier dates are negative numbers and everything else works unchanged. Dates in the distant past are handled on the proleptic Gregorian calendar, which means the calendar rules in use today are projected backwards rather than switching to the Julian calendar at any point.
No. The whole calculation runs in your browser and there is no server behind it. Saved setups and history are stored in this browser only, which also means clearing them from the Settings tab is final.
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