counting chars using bash

I'm fairly new to bash, and also I'm attempting to count the variety of chars in a documents. I created the adhering to function:

function chars(){
    m=$(cat $1)
    m=${#m}
    echo $m
}

calling it with echo $(chars $2) results on a documents the number 524, while calling wc -c on the very same documents results 525. What creates the distinction? Just how can I get the very same outcome? (and also as a side inquiry - can I incorporate both first lines of my function right into one?)