Made for PaperOpen studio
Days between dates

How long is it, exactly?

Count the days between two dates, in calendar days, whole weeks, and working days. Everything is calculated in this browser tab — no dates are sent anywhere.

Result358 days

The start date is excluded and the end date is counted, which is the usual convention.

Or
11 months, 24 days
Weeks
51 + 1d
Business days
245
ISO weeks
W53 → W51

Friday, January 1, 2027 → Saturday, December 25, 2027. Business days exclude weekends and observed U.S. federal holidays.

What the four figures mean

Days is the plain calendar count. Years, months and days is the same gap expressed the way people actually say it, counting whole calendar months rather than dividing by an average. Weeks shows complete seven-day blocks plus any remainder. Business days counts only Monday to Friday and skips observed U.S. federal holidays.

Inclusive or exclusive?

This trips people up more than the arithmetic does. Counting from 1 January to 2 January gives oneday by the ordinary convention — you exclude the day you start on. But a contract that says “within 30 days” or a notice period often means both endpoints count, which gives a different answer.

The checkbox switches between the two, so you can match whichever rule governs your situation rather than guessing. If a deadline matters, check which convention the governing document uses.

When to use business days instead

Filing windows, payment terms, shipping estimates, and notice periods are frequently written in working days. Because weekends and holidays are skipped, ten business days is normally two calendar weeks — but around Thanksgiving or Christmas it stretches further. The business day calculator handles that case directly, including adding or subtracting a number of working days from a date.

Common questions

Does the calculator include the first and last day?
By default it excludes the start date and counts the end date, which is the usual convention — 1 January to 2 January is one day. Tick "count both the first and last day" for an inclusive count, which is what contracts and notice periods often mean.
What is the difference between calendar days and business days?
Calendar days count every day. Business days count only Monday to Friday and exclude observed U.S. federal holidays. A two-week gap is 14 calendar days but usually 10 business days.
Why does the years-months-days figure not match dividing by 365?
Because months have different lengths and years can be 365 or 366 days. The breakdown counts whole calendar months from the start date, which is how people normally describe a duration — 1 January to 1 March is "two months", not "59 days divided by 30.4".
Can I count backwards?
Yes. If the end date falls before the start date, the calculator counts backwards and reports the absolute number of days.
Are my dates sent anywhere?
No. The calculation runs entirely in your browser tab. Nothing is uploaded, and the dates are not written into the address bar or saved.

Related tools

Counting toward a holiday? Every federal holiday page shows how many days away it is. For week numbers, see the ISO week calendars, and to see a span laid out on paper, print a monthly calendar.