javascript: calculate x% of a number
Solution 1:
var result = (35.8 / 100) * 10000;
(Thank you jball for this change of order of operations. I didn't consider it).
Solution 2:
This is what I would do:
// num is your number
// amount is your percentage
function per(num, amount){
return num*amount/100;
}
...
<html goes here>
...
alert(per(10000, 35.8));
Solution 3:
Your percentage divided by 100 (to get the percentage between 0 and 1) times by the number
35.8/100*10000
Solution 4:
Best thing is to memorize balance equation in natural way.
Amount / Whole = Percentage / 100
usually You have one variable missing, in this case it is Amount
Amount / 10000 = 35.8 / 100
then you have high school math (proportion) to multiple outer from both sides and inner from both sides.
Amount * 100 = 358 000
Amount = 3580
It works the same in all languages and on paper. JavaScript is no exception.
Solution 5:
I use two very useful JS functions: http://blog.bassta.bg/2013/05/rangetopercent-and-percenttorange/
function rangeToPercent(number, min, max){
return ((number - min) / (max - min));
}
and
function percentToRange(percent, min, max) {
return((max - min) * percent + min);
}