This week is ...

 

Week 13

Week 13 is from Monday, March 23, 2026 until (and including) Sunday, March 29, 2026.

Week number according to the ISO 8601 standard (more info), weeks starting on Monday. The first week of the year is the week that contains that year's first Thursday (first 4-day week).
ISO representation: 2026-W13

The highest week number in a year is either 52 or 53. 2026 has 53 weeks.

Other systems include the US system (weeks starting on Sunday). In 2026, US week numbers match ISO week numbers for most dates (except on Sundays and around the turn of the year). The current US week number is week 13.

This page was generated on Thursday, March 26, 2026.

Lists of week numbers by year : 2025 - 2026 - 2027 - 2028 ...

Programming routines

Jumplist:

C/AL (Microsoft Dynamics NAV):

MESSAGE(FORMAT(CALCDATE('CW', TODAY), 0, '<week>'));

C#

See the ISO 8601 update on Stack Overflow

C++

C++20, using the chrono library and std::format: 
#include <iostream>
#include <chrono>
#include <format>

int main() {
    auto now = std::chrono::system_clock::now();

    // Format using the ISO 8601 week specifier (%V)
    // %V: ISO 8601 week number (01-53)
    // %G: ISO 8601 year (can differ from calendar year near Jan 1st)
    std::string week_num = std::format("{:%V}", now);
    std::string iso_year = std::format("{:%G}", now);

    std::cout << "ISO 8601 Week Number: " << week_num << std::endl;
    std::cout << "ISO 8601 Year: " << iso_year << std::endl;

    return 0;
}

Go

year, week := time.Now().ISOWeek()

Google Sheets

=WEEKNUM(TODAY(),21)

Type (here '21') is compatible with Excel/LibreOffice, 21 is ISO 8601

iPhone/Mac

[NSString stringWithFormat:@"Week %d",
[calendar ordinalityOfUnit:NSWeekCalendarUnit inUnit:NSYearCalendarUnit forDate:date]];

iPhone/iOS/Swift

let gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
gregorian.firstWeekday = 2 // Monday
gregorian.minimumDaysInFirstWeek = 4
let components =
    gregorian.components(.WeekOfYearCalendarUnit | .YearForWeekOfYearCalendarUnit, fromDate: date)
let week = components.weekOfYear
let year = components.yearForWeekOfYear

iSeries SQL

SELECT WEEK(NOW()) from sysibm.sysdummy1

Java

Calendar now = Calendar.getInstance();
now.get(Calendar.WEEK_OF_YEAR);

Use WEEK_OF_YEAR in the Calendar class.
More info on Stack Overflow

JavaScript

Date.prototype.getWeek = function () {
    var target  = new Date(this.valueOf());
    var dayNr   = (this.getDay() + 6) % 7;
    target.setDate(target.getDate() - dayNr + 3);
    var firstThursday = target.valueOf();
    target.setMonth(0, 1);
    if (target.getDay() != 4) {
        target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7);
    }
    return 1 + Math.ceil((firstThursday - target) / 604800000);
}

var d= new Date();
alert(d.getWeek());

Extend the Date class using the above code.

Linux/Unix shell (bash)

date +%V

Returns the ISO 8601 week number.
Other formats under 'Ruby'. More details in the Linux Programmer's Manual

Lua

Current_week = os.date("%V")

Formats: see formats under 'Ruby'.

MS SQL

SELECT DATEPART( wk, GETDATE() )

Microsoft Excel / LibreOffice Calc

=ISOWEEKNUM(TODAY())
or (in older versions):
=WEEKNUM(TODAY(),21)

Where the return type '21' is ISO 8601 (week starting on Monday).

In Excel 2007 your best choice is WEEKNUM(TODAY(),2) (2=week starting Monday).
WEEKNUM(TODAY()) will show the week number with weeks starting on Sunday (return type = 1).

MySQL

SELECT WEEKOFYEAR(NOW())

Replace now() with other dates eg. SELECT WEEKOFYEAR('2026-02-20');
(You can also use the WEEK function with mode=3 select week(now(),3))

Oracle

SELECT to_char(sysdate, 'IW') FROM DUAL

IW: Week of year (1-52 or 1-53) based on the ISO 8601 standard.
WW: Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year (Mostly NOT used)

PERL

my $weekNumber = POSIX::strftime("%V", gmtime time);

Replace time with other epoch/UNIX timestamps for other week numbers.

PHP

$weekNumber = date("W");

or date("W", epoch) for other week numbers. Remember to use capital 'W' not 'w'.

PostgreSQL

SELECT EXTRACT(WEEK FROM current_date())

Python

datetime.date.today().isocalendar()[1]

R

lubridate::week()

Ruby

week_number = Time.now.strftime("%U")

Replace Time.now with Time.local(year,month,day) for other dates.
Formats:
%U - Week number of the year, starting with the first Sunday as the first day of the first week (00..53)
%V - Week number of year according to ISO 8601 (01..53)
%W - Week number of the year, starting with the first Monday as the first day of the first week (00..53)

Windows PowerShell

Get-Date -UFormat %V
# or
"{0:d2}" -f ($(Get-Culture).Calendar.GetWeekOfYear($(Get-Date),
  [System.Globalization.CalendarWeekRule]::FirstFourDayWeek, [DayOfWeek]::Monday))

X++ (Microsoft Dynamics AX)

int weeknum;
weeknum = weekOfYear(today());

 
Thanks to everyone who sent me corrections and updates!