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How to round up a number in Javascript?

People also ask

How do you round decimals in JavaScript?

Use the . toFixed() Method to Round a Number To2 Decimal Places in JavaScript. We apply the . toFixed() method on the number and pass the number of digits after the decimal as the argument.

How do you round to 2 digits in JavaScript?

Use the toFixed() method to round a number to 2 decimal places, e.g. const result = num. toFixed(2) . The toFixed method will round and format the number to 2 decimal places. Copied!

How do you round the number 7.25 to the nearest integer in JavaScript?

The Math. round() function in JavaScript is used to round the number passed as parameter to its nearest integer. Parameters : The number to be rounded to its nearest integer.

How do you round to 5 in JavaScript?

To round a number to the nearest 5, call the Math. round() function, passing it the number divided by 5 and multiply the result by 5 .


/**
 * @param num The number to round
 * @param precision The number of decimal places to preserve
 */
function roundUp(num, precision) {
  precision = Math.pow(10, precision)
  return Math.ceil(num * precision) / precision
}

roundUp(192.168, 1) //=> 192.2

Little late but, can create a reusable javascript function for this purpose:

// Arguments: number to round, number of decimal places
function roundNumber(rnum, rlength) { 
    var newnumber = Math.round(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
    return newnumber;
}

Call the function as

alert(roundNumber(192.168,2));

Normal rounding will work with a small tweak:

Math.round(price * 10)/10

and if you want to keep a currency format, you can use the Number method .toFixed()

(Math.round(price * 10)/10).toFixed(2)

Though this will make it a String =)


Very near to TheEye answer, but I change a little thing to make it work:

var num = 192.16;
    
console.log(    Math.ceil(num * 10) / 10    );

The OP expects two things:
A. to round up to the higher tenths, and
B. to show a zero in the hundredths place (a typical need with currency).

Meeting both requirement would seem to necessitate a separate method for each of the above. Here's an approach that builds on suryakiran's suggested answer:

//Arguments: number to round, number of decimal places.

function roundPrice(rnum, rlength) {
    var newnumber = Math.ceil(rnum * Math.pow(10, rlength-1)) / Math.pow(10, rlength-1);
    var toTenths = newnumber.toFixed(rlength);
    return toTenths;
}

alert(roundPrice(678.91011,2)); // returns 679.00
alert(roundPrice(876.54321,2)); // returns 876.60

Important note: this solution produces a very different result with negative and exponential numbers.

For the sake of comparison between this answer and two that are very similar, see the following 2 approaches. The first simply rounds to the nearest hundredth per usual, and the second simply rounds up to the nearest hundredth (larger).

function roundNumber(rnum, rlength) { 
    var newnumber = Math.round(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
    return newnumber;
}

alert(roundNumber(678.91011,2)); // returns 678.91

function ceilNumber(rnum, rlength) { 
    var newnumber = Math.ceil(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
    return newnumber;
}

alert(ceilNumber(678.91011,2)); // returns 678.92

ok, this has been answered, but I thought you might like to see my answer that calls the math.pow() function once. I guess I like keeping things DRY.

function roundIt(num, precision) {
    var rounder = Math.pow(10, precision);
    return (Math.round(num * rounder) / rounder).toFixed(precision)
};

It kind of puts it all together. Replace Math.round() with Math.ceil() to round-up instead of rounding-off, which is what the OP wanted.