Calculating Student Age Using PHP Date Functions

The article begins with a requirement analysis: to display a student's age accurately and quickly, the system should store the student's birth year, month, and day, retrieve the current date, and compute the age.

It then outlines the design thinking, asking how to define variables for student information, how to store birth components, how to obtain the current year/month/day, how to calculate the full years elapsed, and how to determine whether the birthday has passed.

A brief knowledge section introduces PHP's Date/Time functions, especially the date() function, its syntax date(format, timestamp), and common format characters such as Y, n, and j.

Finally, the implementation code is provided:

<?php
// Define variables for student's birth year, month, day
$stu_by = 2001;
$stu_bm = 8;
$stu_bd = 07;
// Get current year, month, day
$cur_y = date('Y'); // 4‑digit year
$cur_m = date('n'); // month without leading zero
$cur_d = date('j'); // day without leading zero
// Calculate age
$age = $cur_y - $stu_by;
// Adjust if birthday not yet occurred this year
if ($cur_m < $stu_bm || ($cur_m == $stu_bm && $cur_d < $stu_bd)) {
    $age--;
}
?>

The output shows that on 2 November 2020 the script correctly reports the student's age, demonstrating the handling of different current months (e.g., May vs. October) and the birthday‑passed logic.