relative-time.php

<?php
function findTimeAgo($past, $now = "now") {
    // sets the default timezone if required 
    // list of supported timezone identifiers 
    // http://php.net/manual/en/timezones.php
    // date_default_timezone_set("Asia/Calcutta"); 
    $secondsPerMinute = 60;
    $secondsPerHour = 3600;
    $secondsPerDay = 86400;
    $secondsPerMonth = 2592000;
    $secondsPerYear = 31104000;
    // finds the past in datetime
    $past = strtotime($past);
    // finds the current datetime
    $now = strtotime($now);
    
    // creates the "time ago" string. This always starts with an "about..."
    $timeAgo = "";
    
    // finds the time difference
    $timeDifference = $now - $past;
    
    // less than 29secs
    if($timeDifference <= 29) {
      $timeAgo = "less than a minute";
    }
    // more than 29secs and less than 1min29secss
    else if($timeDifference > 29 && $timeDifference <= 89) {
      $timeAgo = "1 minute";
    }
    // between 1min30secs and 44mins29secs
    else if($timeDifference > 89 &&
      $timeDifference <= (($secondsPerMinute * 44) + 29)
    ) {
      $minutes = floor($timeDifference / $secondsPerMinute);
      $timeAgo = $minutes." minutes";
    }
    // between 44mins30secs and 1hour29mins29secs
    else if(
      $timeDifference > (($secondsPerMinute * 44) + 29)
      &&
      $timeDifference < (($secondsPerMinute * 89) + 29)
    ) {
      $timeAgo = "about 1 hour";
    }
    // between 1hour29mins30secs and 23hours59mins29secs
    else if(
      $timeDifference > (
        ($secondsPerMinute * 89) +
        29
      )
      &&
      $timeDifference <= (
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
    ) {
      $hours = floor($timeDifference / $secondsPerHour);
      $timeAgo = $hours." hours";
    }
    // between 23hours59mins30secs and 47hours59mins29secs
    else if(
      $timeDifference > (
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
      &&
      $timeDifference <= (
        ($secondsPerHour * 47) +
        ($secondsPerMinute * 59) +
        29
      )
    ) {
      $timeAgo = "1 day";
    }
    // between 47hours59mins30secs and 29days23hours59mins29secs
    else if(
      $timeDifference > (
        ($secondsPerHour * 47) +
        ($secondsPerMinute * 59) +
        29
      )
      &&
      $timeDifference <= (
        ($secondsPerDay * 29) +
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
    ) {
      $days = floor($timeDifference / $secondsPerDay);
      $timeAgo = $days." days";
    }
    // between 29days23hours59mins30secs and 59days23hours59mins29secs
    else if(
      $timeDifference > (
        ($secondsPerDay * 29) +
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
      &&
      $timeDifference <= (
        ($secondsPerDay * 59) +
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
    ) {
      $timeAgo = "about 1 month";
    }
    // between 59days23hours59mins30secs and 1year (minus 1sec)
    else if(
      $timeDifference > (
        ($secondsPerDay * 59) + 
        ($secondsPerHour * 23) +
        ($secondsPerMinute * 59) +
        29
      )
      &&
      $timeDifference < $secondsPerYear
    ) {
      $months = round($timeDifference / $secondsPerMonth);
      // if months is 1, then set it to 2, because we are "past" 1 month
      if($months == 1) {
        $months = 2;
      }
      
      $timeAgo = $months." months";
    }
    // between 1year and 2years (minus 1sec)
    else if(
      $timeDifference >= $secondsPerYear
      &&
      $timeDifference < ($secondsPerYear * 2)
    ) {
      $timeAgo = "about 1 year";
    }
    // 2years or more
    else {
      $years = floor($timeDifference / $secondsPerYear);
      $timeAgo = "over ".$years." years";
    }
    
    return $timeAgo." ago";
  }

//current time: 2015-03-29 08:03:07

$time1 = findTimeAgo("2015-03-29 00:30:30"); // 7 hours ago

$time2 = findTimeAgo("2015-03-28 17:24:42"); //14 hours ago

$time3 = findTimeAgo("2015-03-17 17:24:42"); //11 days ago

$time4 = findTimeAgo("2015-01-02 17:24:42"); //3 months ago

$time5 = findTimeAgo("2014-01-02 00:00:00"); //about 1 year ago