Calculate value to procent

[Tokatubs]

I'm trying to figure out the calculation for finding the percentage between two values that a third value is.
Example: The range is 46 to 195 m3h. The value 46 would 0%, and the value 195 would be 100% of the range. What percentage of this range is the value 65?
rangeMin=46
rangeMax=195
inputValue=65
inputPercentage = ?

Usage of this is i have calculated three Vav. And then i need the sum of these to give me back a procent value to give the regulator.

Found this code on different site. But i think that this is missing something 

Code:

function rangePercentage (input, range_min, range_max, range_2ndMax){

    var percentage = ((input - range_min) * 100) / (range_max - range_min);

    if (percentage > 100) {

        if (typeof range_2ndMax !== 'undefined'){
            percentage = ((range_2ndMax - input) * 100) / (range_2ndMax - range_max);
            if (percentage < 0) {
                percentage = 0;
            }
        } else {
            percentage = 100;
        }

    } else if (percentage < 0){
        percentage = 0;
    }

    return percentage;
}