PHP Date Exercises : Start and end date of a week (by week number) of a particular year

Last update on June 03 2025 12:56:05 (UTC/GMT +8 hours)

17. Start and End Date of Week by Week Number

Write a PHP function to get start and end date of a week (by week number) of a particular year.

Sample week and year : 12, 2014

Sample Solution:

PHP Code:

<?php
function Start_End_Date_of_a_week($week, $year)
{
    $time = strtotime("1 January $year", time()); // Getting the timestamp for January 1st of the given year.
    $day = date('w', $time); // Getting the numeric representation of the day of the week for January 1st.
    $time += ((7*$week)+1-$day)*24*3600; // Calculating the timestamp for the starting day of the given week.
    $dates[0] = date('Y-n-j', $time); // Formatting the starting date of the week.
    $time += 6*24*3600; // Adding six days to get the timestamp for the end of the week.
    $dates[1] = date('Y-n-j', $time); // Formatting the end date of the week.
    return $dates; // Returning the array containing the starting and end dates of the week.
}

$result = Start_End_Date_of_a_week(12, 2014); // Calling the function to get the starting and end dates of the 12th week of 2014.
echo 'Starting date of the week: '. $result[0]."\n"; // Outputting the starting date of the week.
echo 'End date the week: '. $result[1]; // Outputting the end date of the week.
?>

Output:

Starting date of the week: 2014-3-24                        
End date the week: 2014-3-30

Explanation:

In the exercise above,

function Start_End_Date_of_a_week($week, $year): Declaring a function named Start_End_Date_of_a_week which accepts two parameters: '$week' and '$year'.
$time = strtotime("1 January $year", time());: Get the timestamp for January 1st of the given year.
$day = date('w', $time);: Get the numerical representation of the day of the week for January 1st.
$time += ((7*$week)+1-$day)*24*3600;: Calculates the timestamp for the starting day of the given week based on the given week number and year.
$dates[0] = date('Y-n-j', $time);: Format the starting date of the week.
$time += 6*24*3600;: Add six days to the timestamp to get the timestamp for the end of the week.
$dates[1] = date('Y-n-j', $time);: Format the end date of the week.
return $dates;: Returns the array containing the starting and end dates of the week.
$result = Start_End_Date_of_a_week(12, 2014);: Calling the function to get the starting and end dates of the 12th week of 2014.
echo 'Starting date of the week: '. $result[0]."\n";: Outputting the starting date of the week.
echo 'End date the week: '. $result[1];: Outputs the end date of the week.

Flowchart :

Flowchart: Start and end date of a week (by week number) of a particular year

For more Practice: Solve these Related Problems:

Write a PHP function that, given a week number and year, returns the start (Monday) and end (Sunday) dates of that week.
Write a PHP script to calculate the week range for a given week number and display it in a formatted string.
Write a PHP program to iterate through all weeks of a year and output their start and end dates.
Write a PHP script to compute the week boundary dates for a user-provided week number and then calculate the number of days in that week.

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PHP Code Editor:

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