Days between
US calendar
Calendar days in the range
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Business days—
Calendar days—
Weekend days—
Holidays—
The exact number of days between two dates, with the inclusive total beside it and the span broken into weeks, months, weekends, and working days. The two conventions disagree by one day, and which one you owe someone is usually the whole question.
Step by step
01Enter the two dates
Order does not matter — the span is reported the same either way. Both dates are read as plain calendar dates with no time zone attached, so nothing shifts underneath you at midnight.
02Read the exclusive count first
The headline number is the plain difference between the dates: the number of nights, the number the calendar arithmetic gives you. This is the figure almost every system means by 'days between'.
03Check the inclusive total if both days count
Shown alongside, one higher, for the cases where the first day is itself part of what you are counting — a leave request, a conference, a warranty that starts the day it is issued.
04Use the breakdown to sanity-check
Weeks and remainder days, weekend days, and the working-day count are all derived from the same span, so a number that looks wrong can be traced to the convention that produced it rather than guessed at.
Worked example
The most-quoted span there is, counted both ways. The gap between them is the whole reason contracts specify a convention.
Given
The same year, two conventions
exclusive count 364 nights between
inclusive count 365 both days counted
whole weeks 52 remainder 0 days
weekend days 104 52 Saturdays, 52 Sundays
both dates fall on a Thursday, which is
what a 364-day span means: a whole number
of weeks. add a leap day and it does not.A year is 365 days but the span between its first and last day is 364, and both numbers are correct answers to differently-worded questions. This is the error that shows up in billing: charge the inclusive count for something metered nightly and every invoice is one day over, every time, in a way that reconciles perfectly against itself and is never caught internally.
Before you quote a number
Inclusive and exclusive are both defensible
There is no default. A span of nights is exclusive; a span of days served, days of cover, or days of leave is usually inclusive. When a contract says 'within 30 days' without saying which, that ambiguity is worth one day and has been litigated more than once.
Months are not a unit of length
31 January plus one month is 28 February in most systems and 3 March in some others, and neither is wrong — the operation is genuinely undefined at month ends. Any deadline that matters should be expressed in days, or in a named date, not in months.
Leap days are counted, not adjusted for
The span walks real dates, so 29 February 2028 is one day like any other. This means two spans of 'one year' can differ by a day depending on where they start, which is exactly right and routinely surprising.
No time zone is applied
Both inputs are plain calendar dates. Nothing is converted to UTC and nothing shifts at a boundary — a mistake that turns 'days between' into 'days between, off by one, for users east of you' in a surprising number of production systems.
Age is an inclusive-exclusive problem in disguise
Someone born on 1 January is not one year old until the next 1 January, which is the exclusive convention. Counting inclusively makes every birthday arrive a day early, and it is the same off-by-one as the billing case wearing different clothes.
Everything is computed locally
The arithmetic runs in the page, so it works offline and no dates are sent anywhere — which matters when the dates are a medical appointment, a legal deadline, or an unannounced launch.
The judgement call
The convention follows from what is being measured, not from preference.
Hotel nights, car hire, daily rental
Exclusive
You are billed per night, and the number of nights is the plain difference between the dates.
Days of annual leave taken
Inclusive
The first day off is a day off. Counting exclusively gives every employee one day back per request.
Interest, rent, or anything accruing daily
Exclusive
Accrual is per elapsed day. This is the count, and it does not pause for weekends.
Someone's age, or time since an event
Exclusive
A year has not passed until the anniversary arrives, which the exclusive count is what expresses.
'Within 30 days' in a contract
Read the contract
It is genuinely ambiguous. If the document does not define it, both readings are arguable and the difference is a day.
A deadline in working days
Business days calculator
Weekends and holidays have to come out, which this page deliberately does not do.
Reference
FAQ
Subtract the earlier date from the later one and you get the exclusive count — the number of nights between them. Counting both endpoints as well gives the inclusive count, which is one higher. Neither is more correct; they answer different questions, so both are shown.
It reports both. The headline figure is the plain span between the two dates, and the inclusive total is shown beside it. A hotel bills the exclusive count, a holiday allowance usually charges the inclusive one, and a contract will normally say which it means.
Yes. The count walks real calendar dates, so any 29 February inside the range is counted like any other day. A year-long span that crosses one is 366 days, not 365.
Because months are not a fixed length. From 31 January to 28 February is one month by name and 28 days by count, and the same 28 days starting in March is not a month at all. The day count is exact; the month breakdown is a reading aid, and where the two disagree the day count is the one to quote.
Yes, on the business days calculator, which excludes weekends and the US or UK public holidays in the range. This page counts every day, which is what you want for anything that accrues daily — interest, rent, storage, or age.
The arithmetic runs in your browser. No dates are transmitted, and the page works with no network at all.
Keep going
Business Days Calculator
The same span with weekends and public holidays taken out.
Add or Subtract Days
Go the other way: a date, a number of days, and where it lands.
Timestamp Converter
Turn a system timestamp into the date you are counting from.
Time Zone Converter
Check what a deadline hour means for the other party.