Strlen is not giving correct output - php

Question

I have a string which I retrieve from a database, I want to calculate the length of the string without spaces but it is displaying a larger value of length(21 characters greater than the actual count) I have removed tab and newline characters and also the php and html tags but no result! I have tried almost every function on the w3schools php reference but I'm unable to find any success. I also have observed that if I don't retrieve the value from the database and input it like this:
$string = "my string";
I get the correct length, please help me. Here is the code:
if($res_tutor[0]['tutor_experience']){
$str = trim(strip_tags($res_tutor[0]['tutor_experience']));
$str = $this->real_string($str);
$space = substr_count($str, ' ');
$experience = strlen($str) - $space;
function real_string($str)
{
$search = array("\t","\n","\r\n","\0","\v");
$replace = array('','','','','');
$str = str_replace($search,$replace,$str);
return $str;
}
And this is the string from the database but as you can see above I have removed all php and html tags using strip_tags() :
<span class=\"experience_font\">You are encouraged to write a short description of yourself, teaching experience and teaching method. You may use the guidelines below to assist you in your writing.<br />
<br />
.Years of teaching experience<br />
.Total number of students taught<br />
.Levels & subjects that you have taught<br />
.The improvements that your students have made<br />
.Other achievements/experience (Relief teaching, a tutor in a tuition centre, Dean's list, scholarship, public speaking etc.)<br />
.For Music (Gigs at Esplanade, Your performances in various locations etc.)</span><br />
</p>
and when I print it, it displays as:
<span class=\"experience_font\">You are encouraged to write a short description of yourself, teaching experience and teaching method. You may use the guidelines below to assist you in your writing.<br />
<br />
.Years of teaching experience<br />
.Total number of students taught<br />
.Levels & subjects that you have taught<br />
.The improvements that your students have made<br />
.Other achievements/experience (Relief teaching, a tutor in a tuition centre, Dean's list, scholarship, public speaking etc.)<br />
.For Music (Gigs at Esplanade, Your performances in various locations etc.)</span><br />
</p>

Answer 1

#Svetilo, not to be rude just wanted to post my findings, your str_replace worked wonderfully, except for the fact that I was still outputting incorrect values with it in the order that you currently have, I found that the following worked flawlessly.
$string = str_replace(array("\t","\r\n","\n","\0","\v"," "),'', $string);
mb_strlen($string, "UTF-8");
Changing around the \r\n & \n made the str_replace not strip out the \n from the \r\n leaving it just a \r.
Cheers.

Answer 2

Try using mb_strlen. http://php.net/manual/en/function.mb-strlen.php
Its more more precise.
mb_strlen($str,"UTF-8")
Where UTF-8 is your default encoding...
To remove all freespaces try something like that..
$string = str_replace(array("\t","\n","\r\n","\0","\v"," "),"",$string);
mb_strlen($string, "UTF-8");