PHP subtract 1 month from date formatted with date ('m-Y')

Question

I'm trying to subtract 1 month from a date.

$today = date('m-Y');

This gives: 08-2016

How can I subtract a month to get 07-2016?

Knockout

@user1234 please don't abuse code blocks. – Cloraclorinda

(DATE_SUB(curdate(), INTERVAL 1 MONTH)) – Basically

Does this answer your question? PHP strtotime: Get previous month – Clausen

Answer 1

 <?php 
  echo $newdate = date("m-Y", strtotime("-1 months"));

output

07-2016

Undulate

N.B.: before using this example, read the warning about the edge-cases below – Inguinal

strtotime("-1 months") does not work if you have 31 days. – Starknaked

as @FakhruddinUjjainwala pointed out I found a solution preventing this with a second strtotime(). Just look at my provided anwser. – Wesleyanism

echo date('Y-m', strtotime('2021-07-31' . ' - 1 month')); check this this will return 2021-07.. similarly check for March 31st or March 30th and even March 29th too if not leap year – Ose

Answer 2

Warning! The above-mentioned examples won't work if call them at the end of a month.

<?php
$now = mktime(0, 0, 0, 10, 31, 2017);
echo date("m-Y", $now)."\n";
echo date("m-Y", strtotime("-1 months", $now))."\n";

will output:

10-2017
10-2017

The following example will produce the same result:

$date = new DateTime('2017-10-31 00:00:00');
echo $date->format('m-Y')."\n";
$date->modify('-1 month');
echo $date->format('m-Y')."\n";

Plenty of ways how to solve the issue can be found in another thread: PHP DateTime::modify adding and subtracting months

Inguinal

The reason behind it does not work is because the following: What's last month of 2017-10-29? 2017-09-29. And last month of 2017-10-30? 2017-09-30. And what about last month of 2017-10-31? In theory 2017-09-31, but this day does not exist, and then it maps onto 2017-10-01. – Landseer

The problem stated above by @XaviMontero can be solved with: $date->modify('first day of -1 month'); – Roughcast

Answer 3

Try this,

$today = date('m-Y');
$newdate = date('m-Y', strtotime('-1 months', strtotime($today))); 
echo $newdate;

Roughneck

should have included that this is looping around as I want to get the last 12 months starting from the current month. – Knockout

You can use it in loop – Roughneck

it will not work and it's output 12-1969 – Romanist

Answer 4

Depending on your PHP version you can use DateTime object (introduced in PHP 5.2 if I remember correctly):

<?php
$today = new DateTime(); // This will create a DateTime object with the current date
$today->modify('-1 month');

You can pass another date to the constructor, it does not have to be the current date. More information: http://php.net/manual/en/datetime.modify.php

Sandstone

Answer 5

$lastMonth = date('Y-m', strtotime('-1 MONTH'));

Microdot

While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value. – Pomerania

Answer 6

Try this,

$effectiveDate = date('2018-01'); <br> 
echo 'Date'.$effectiveDate;<br>
$effectiveDate = date('m-y', strtotime($effectiveDate.'+-1 months'));<br>
echo 'Date'.$effectiveDate;

Weakminded

Answer 7

I used this to prevent the "last days of month"-error. I just use a second strtotime() to set the date to the first day of the month:

<?php
echo $newdate = date("m-Y", strtotime("-1 months", strtotime(date("Y-m")."-01")));

Wesleyanism

Answer 8

if(date("d") > 28){
    $date = date("Y-m", strtotime("-".$loop." months -2 Day"));
} else {
    $date = date("Y-m", strtotime("-".$loop." months"));
}

Christoper

This code wont skip the february even if am at the month end. – Christoper

Answer 9

First change the date format m-Y to Y-m

    $date = $_POST('date'); // Post month
    or
    $date = date('m-Y'); // currrent month

    $date_txt = date_create_from_format('m-Y', $date);
    $change_format = date_format($date_txt, 'Y-m');

This code minus 1 month to the given date

    $final_date = new DateTime($change_format);
    $final_date->modify('-1 month');
    $output = $final_date->format('m-Y');

Accrete

Answer 10

$currentMonth = date('m', time());
$currentDay = date('d',time());
$currentYear = date('Y',time());
$lastMonth = $currentMonth -1;
$one_month_ago=mkdate(0,0,0,$one_month_ago,$currentDay,$currentYear);

This could be rewritten more elegantly, but it works for me

Mom

This won't work if the current month is January – Dan

Answer 11

I realize this is an old post, but I've been solving the same issue, and here is what I came up with to account for all the variability. This function is just trying to get relative dates, so same day of prior month, or last day of month if you are on the last day, regardless of exactly how many days a month has. So goal is given '2010-03-31' and subtract a month, we should output '2010-02-28'.

private function subtractRelativeMonth(DateTime $incomingDate): DateTime
{
    $year = $incomingDate->format('Y');
    $month = $incomingDate->format('m');
    $day = $incomingDate->format('d');
    $daysInOldMonth = cal_days_in_month(CAL_GREGORIAN, $month, $year);
    if ($month == 1) { //It's January, so we have to go back to December of prior year
        $month = 12;
        $year--;
    } else {
        $month--;
    }
    $daysInNewMonth = cal_days_in_month(CAL_GREGORIAN, $month, $year);
    if ($day > $daysInNewMonth && $month == 2) { //New month is Feb
        $day = $daysInNewMonth;
    }
    if ($day > 29 && $daysInOldMonth > $daysInNewMonth) {
        $day = $daysInNewMonth;
    }
    $adjustedDate = new \DateTime($year . '-' . $month . '-' . $day);
    return $adjustedDate;
}

Piscator