Example:
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. 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 = ?
Well, I would use the formula
((input - min) * 100) / (max - min) For your example it would be
((65 - 46) * 100) / (195 - 46) = 12.75 Or a little bit longer
range = max - min correctedStartValue = input - min percentage = (correctedStartValue * 100) / range If you already have the percentage and you're looking for the "input value" in a given range, then you can use the adjusted formula provided by Dustin in the comments:
value = (percentage * (max - min) / 100) + min 
val = ((percent * (max - min) / 100) + min
10 - (-10) which is 10 + 10 and 20. Looks correct. Then assume input is 8. correctedStartValue would be 8 - (-10) = 18. That first looks strange, but lets keep going. The result would be (18*100) / 20 = 90%. And 90% looks fine to me for value 8 between -10 and 10.correctedStartValue will be negative as well.I put together this function to calculate it. It also gives the ability to set a mid way 100% point that then goes back down.
Usage
//[] = optional rangePercentage(input, minimum_range, maximum_normal_range, [maximum_upper_range]); rangePercentage(250, 0, 500); //returns 50 (as in 50%) rangePercentage(100, 0, 200, 400); //returns 50 rangePercentage(200, 0, 200, 400); //returns 100 rangePercentage(300, 0, 200, 400); //returns 50 The function
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; } If you want to calculate the percentages of a list of values and truncate the values between a max and min you can do something like this:
private getPercentages(arr:number[], min:number=0, max:number=100): number[] { let maxValue = Math.max( ...arr ); return arr.map((el)=>{ let percent = el * 100 / maxValue; return percent * ((max - min) / 100) + min; }); }; Here the function call:
this.getPercentages([20,30,80,200],20,50);
would return
[23, 24.5, 32, 50] where the percentages are relative and placed between the min and max value.
Can be used for scaling any number of variables
Python Implementation:
# List1 will contain all the variables list1 = [] # append all the variables in list1 list1.append(var1) list1.append(var2) list1.append(var3) list1.append(var4) # Sorting the list in ascending order list1.sort(key = None, reverse = False) # Normalizing each variable using ( X_Normalized = (X - X_minimum) / (X_Maximum - X_minimum) ) normalized_var1 = (var1 - list1[0]) / (list1[-1] - list1[0]) normalized_var2 = (var2 - list1[0]) / (list1[-1] - list1[0]) normalized_var3 = (var3 - list1[0]) / (list1[-1] - list1[0]) normalized_var4 = (var4 - list1[0]) / (list1[-1] - list1[0]) 
