round to nearest .25 javascript

Question

I want to convert all numbers to the nearest .25

So...

5 becomes 5.00
2.25 becomes 2.25
4 becomes 4.00
3.5 becomes 3.50

Answer 1

Here’s an implementation of what rslite said:

var number = 5.12345;
number = (Math.round(number * 4) / 4).toFixed(2);

Answer 2

Multiply by 4, round to integer, divide by 4 and format with two decimals.

Answer 3

If speed is your concern, note that you can get about a 30% speed improvement by using:

var nearest = 4;
var rounded = number + nearest/2 - (number+nearest/2) % nearest;

From my website: http://phrogz.net/round-to-nearest-via-modulus-division
Performance tests here: http://jsperf.com/round-to-nearest

Answer 4

Here is a generic function to do rounding. In the examples above, 4 was used because that is in the inverse of .25. This function allows the user to ignore that detail. It doesn't currently support preset precision, but that can easily be added.

function roundToNearest(numToRound, numToRoundTo) {
    numToRoundTo = 1 / (numToRoundTo);

    return Math.round(numToRound * numToRoundTo) / numToRoundTo;
}

Answer 5

Here is @Gumbo's answer in a form of a function:

var roundNearQtr = function(number) {
  return (Math.round(number * 4) / 4).toFixed(2);
};

You can now make calls:

roundNearQtr(5.12345); // 5.00
roundNearQtr(3.23); // 3.25
roundNearQtr(3.13); // 3.25
roundNearQtr(3.1247); // 3.00

Answer 6

function roundToInc(num, inc) {
    const diff = num % inc;
    return diff>inc/2?(num-diff+inc):num-diff;
}

> roundToInc(233223.2342343, 0.01)
233223.23
> roundToInc(505, 5)
505
> roundToInc(507, 5)
505
> roundToInc(508, 5)
510

Answer 7

Use below function, hope it helps

function roundByQuarter(value) {
    var inv = 1.0 / 0.25;
    return Math.round(value * inv) / inv;
}

Call the function as below, will result the nearest Quarter value, that is it will not return .32, .89, .56 but will return .25, .75, .50 decimals only.

roundByQuarter(2.74) = 2.75

roundByQuarter(2.34) = 2.25

roundByQuarter(2.94) = 3.00

roundByQuarter(2.24) = 2.25