How to Get the First and Last Day of a Month, Current Date Parts, and Previous Month Dates in PHP

This article demonstrates several common date‑handling tasks in PHP, including obtaining the first and last day of the current month, extracting the current year, month, day and the number of days in the month, using a custom function with an array to retrieve month boundaries, and calculating the first and last day of the previous month.

1. Get the first and last day of the current month

<?php
$BeginMonthDate = date('Y-m-01', strtotime(date("Y-m-d")));
echo $BeginMonthDate;
echo "<br/>";
echo date('Y-m-d', strtotime("$BeginMonthDate +1 month -1 day"));
echo "<br/>";
?&gt;

Output example:

2021-03-01
2021-03-31

2. Get the current year, month, day and number of days in the month

<?php
echo " 本月共有:" . date("t") . "天";
echo " 当前年份" . date('Y');
echo " 当前月份" . date('m');
echo " 当前几号" . date('d');
echo "<br/>";
?&gt;

Output example:

本月共有:31天 当前年份2021 当前月份03 当前几号31

3. Use a function and array to get the first and last day of the month

<?php
function getthemonth($date) {
    $firstday = date('Y-m-01', strtotime($date));
    $lastday = date('Y-m-d', strtotime("$firstday +1 month -1 day"));
    return array($firstday, $lastday);
}
$today = date("Y-m-d");
$day = getthemonth($today);
echo "当月的第一天: " . $day[0] . " 当月的最后一天: " . $day[1];
echo "<br/>";
?&gt;

Output example:

当月的第一天: 2021-03-01 当月的最后一天: 2021-03-31

4. Get the first and last day of the previous month

<?php
// 上个月第一天:
echo date('Y-m-d', strtotime(date('Y-m-01') . ' -1 month'));
echo "<br>";
// 上个月最后一天:
echo date('Y-m-d', strtotime(date('Y-m-01') . ' -1 day'));
?&gt;

Output example:

2021-02-01
2021-02-28