# JavaScript Round To Nearest Number

The JavaScript Math.round() function will round a decimal to the nearest whole number, but I found that I needed was to round a number to the nearest 10. So after a bit of thinking I realised that I could divide the value by 10, round it using the round() function and then multiply the result by 10.

So taking it a step further I decided to create a function that would round a number to the nearest 10, 100, 1000 or whatever value is entered. If this value is less than 0 then do the reverse by multiplying and dividing the number by the given value of accuracy. Here is the function.

``````function roundNearest(num, acc){
if ( acc < 0 ) {
num *= acc;
num = Math.round(num);
num /= acc;
return num;
} else {
num /= acc;
num = Math.round(num);
num *= acc;
return num;
}
}``````

Here are some tests of the function.

``````alert( roundNearest(12345, 1000) ); // 1200

This function can be simplified a little by putting all of the calculations onto one line.

``````function roundNearest(num, acc){
if ( acc < 0 ) {
return Math.round(num*acc)/acc;
} else {
return Math.round(num/acc)*acc;
}
}``````