date half month not working - php

Question

I tried to do like this
date('Y-m-d', strtotime('0.5 months'));
But it gives me date 1970-01-01
Expected date is 2017-10-15
So the question is why the half month is not working?

Answer 1

You can't use non-integers in a strtotime() relative date format:
number [+-]?[0-9]+
To make this work, you can use either 2 weeks or 15 days (note that these two return different days, since 2 weeks is 14 days):
<?php
echo date("Y-m-d", strtotime("2 weeks")).PHP_EOL; // 2017-10-15
echo date("Y-m-d", strtotime("15 days")).PHP_EOL; // 2017-10-16
echo date("Y-m-d", strtotime("+.5 months")).PHP_EOL; // not valid, returns 1970-01-01
Demo

Answer 2

I think you forgot the Plus singn
Please try with below
date('Y-m-d', strtotime('+ 0.5 months'));
or
date('Y-m-d', strtotime('+ 15 days'));
(If you convert in days)
hope will help you

Answer 3

I'm looking for a solution using only php relative time for a half month. The problem with the previous answers is that they don’t take into account the fluctuation in the amount of days per month. Consider this:
$time = strtotime('last day of feb 2019');
$time = strtotime('-2 weeks', $time);
$formatted_date = date('m/d', $time);
Output is 02/14 which is exactly in the middle of the month. But what about this:
$time = strtotime('last day of jan');
$time = strtotime('-2 weeks', $time);
$formatted_date = date('m/d', $time);
Output is 01/17, which is 1-2 days off from the true middle of the month (01/15.5) depending on if you round up or down.
Also, per the answer with strtotime('+0.5 months'), I know this was addressed, but this is an excerpt straight from the PHP docs:
number is an integer number; if a decimal number is given, the dot (or comma) is likely interpreted as delimiter. For instance, '+1.5 hours' is parsed like '+1 5 hours', not as '+1 hour +30 minutes'.
I’ve experimented with quite a few phrasings to get to the true middle of the month, and I’ve come to the conclusion that it isn’t possible with relative formats alone. So here is my solution:
<?php
function middleOfMonth( $time ) {
$n = cal_days_in_month( CAL_GREGORIAN, date('n', $time), date('Y', $time) );
return $n / 2;
}
$time = strtotime('jan next year');
$middle = middleOfMonth( $time ); // result is 15.5
echo( ceil( $middle ) ); // outputs 16
echo( floor( $middle ) ); // outputs 15