# Week of year calculator

## World's simplest time tool

With this browser-based application, you can find the week of the year for any calendar date. The program counts the number of weeks that have passed since the 1st of January and shows the week number for your given date. You can find the week counter for several dates if you enter them into the input field, each on a separate line. You can also switch between a numeric and textual output format. Created by computer nerds from team Browserling.

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Week of year calculator tool
What is a week of year calculator?

This is a quick online utility for calculating the week number for any calendar date. When you enter a date, it determines what its week number is. For example, the date "2022-01-20" is the 2nd week of the year so the output is "2"; and the date "2023-10-01" is the 40th week of the year, so the output is "40". A common calendar year consists of 52 weeks and 1 extra day and a leap year has 52 weeks and 2 extra days. We use a simple mathematical algorithm to find the week of the year. Our program calculates how many days have passed from the beginning of the year to the specified date and then divides the number of passed days by 7 (the number of days in a week). For example, for the date "2023-10-01" there have been 274 days passed from "2023-01-01" (the beginning of the year), so to get the week number, we divide 274 by 7 and get 40, which means its the 40th week of the year. The input field can process multiple calendar dates at once if you just enter them separated by a newline. You can also change the format of the calculated results using the checkbox in the options. If the checkbox isn't activated, you'll get a purely numeric result "40" for the date "2023-10-01". If the checkbox is activated, you'll get a full sentence as the output that says: "2023-10-01 is 40th week of the year.". If you want to know what day of the year a given date falls on, then you can switch to our find day of the year tool. Timeabulous!

Week of year calculator examples
Click to use

Project Deadline in Weeks

In this example, we enter the deadline date "2022-10-15" for a project that we started in early January of 2022. We use our utility to calculate how many weeks in total we can spend working on the project. In the output, we get the number 42, which means that has to be delivered by the forty-second week of the year.

2022-10-15

42

**Required options**

Print the result in a text form
with the week number as
an ordinal number and
the original date included.

Week Numbers of Quarters

In this example, we determine which week of the year the 1st, 2nd, 3rd, and 4th quarter ends on. We input four dates and find that the first quarter ends on the 13th week, the second on the 26th week, the third on the 40th week, and the fourth on the 53rd week. We enable full-text output format, which also includes the original calendar dates and makes it easier to read the information.

2024-03-31
2024-06-30
2024-09-30
2024-12-31

2024-03-31 is 13th week of the year.
2024-06-30 is 26th week of the year.
2024-09-30 is 40th week of the year.
2024-12-31 is 53rd week of the year.

**Required options**

Print the result in a text form
with the week number as
an ordinal number and
the original date included.

Prime Weeks

This example shows the starting dates for the weeks that are prime weeks. Prime weeks mean that their count in a year is a prime number. The first prime week is the 2nd week that starts on the 8th of January, then the next one is the 3rd week that starts on the 15th of January, then the 5th week that starts on the 29th of January, and so on.

2000-01-08
2000-01-15
2000-01-29
2000-02-12
2000-03-11
2000-03-25
2000-04-22
2000-05-06
2000-06-03
2000-07-15
2000-07-29
2000-09-09
2000-10-07
2000-10-21
2000-11-18
2000-12-30

2
3
5
7
11
13
17
19
23
29
31
37
41
43
47
53

**Required options**

Print the result in a text form
with the week number as
an ordinal number and
the original date included.

Pro tips
Master online time tools

You can pass input to this tool via

__?input__query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!
https://onlinetimetools.com/find-week-of-year

__?input__=2022-10-15&print-date=false
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