Incorrect duration calculation in php

Question

I have to calculate duration between two dates and result it to years, months and date format, but its returning extra one or two days in a month, I couldn't able find where the issue is

Start date - 01-03-2024

End date - 31-03-2024

Duration - 1 month, 2 days (extra two days is wrong)

The function used for computation

function getDuration($startDate, $endDate)
{

    if (empty($startDate) || empty($endDate)) {
        return '';
    }

    $startDateTime = new DateTime($startDate);
    $endDateTime = new DateTime($endDate);

    $endDateTime->modify('+1 day');
    $interval = $startDateTime->diff($endDateTime);

    $duration = '';

    if ($years = $interval->y) {
        $duration .= "$years year" . ($years > 1 ? 's' : '') . ', ';
    }

    if ($months = $interval->m) {
        $duration .= "$months month" . ($months > 1 ? 's' : '') . ', ';
    }

    if ($days = $interval->d) {
        $duration .= "$days day" . ($days > 1 ? 's' : '');
    }

    return rtrim($duration, ', ');
}

Answer 1

The problem here is the start date and end date we pass shouldn't be a string value, We have to convert it to date format if it is in string format

$startDate = date("Y-m-d", strtotime($startDate));
$endDate = date("Y-m-d", strtotime($endDate));

and it Works !!!