How can I parse a string with a comma thousand separator to a number?

Question

I have 2,299.00 as a string and I am trying to parse it to a number. I tried using parseFloat, which results in 2. I guess the comma is the problem, but how would I solve this issue the right way? Just remove the comma?

var x = parseFloat("2,299.00")
console.log(x);

Answer 1

Yes remove the commas:

let output = parseFloat("2,299.00".replace(/,/g, ''));
console.log(output);

Answer 2

Removing commas is potentially dangerous because, as others have mentioned in the comments, many locales use a comma to mean something different (like a decimal place).

I don't know where you got your string from, but in some places in the world "2,299.00" = 2.299

The Intl object could have been a nice way to tackle this problem, but somehow they managed to ship the spec with only a Intl.NumberFormat.format() API and no parse counterpart :(

The only way to parse a string with cultural numeric characters in it to a machine recognisable number in any i18n sane way is to use a library that leverages CLDR data to cover off all possible ways of formatting number strings http://cldr.unicode.org/

The two best JS options I've come across for this so far:

• https://github.com/google/closure-library/tree/master/closure/goog/i18n
• https://github.com/globalizejs/globalize

Answer 3

On modern browsers you can use the built in Intl.NumberFormat to detect the browser's number formatting and normalize the input to match.

function parseNumber(value, locales = navigator.languages) {
  const example = Intl.NumberFormat(locales).format('1.1');
  const cleanPattern = new RegExp(`[^-+0-9${ example.charAt( 1 ) }]`, 'g');
  const cleaned = value.replace(cleanPattern, '');
  const normalized = cleaned.replace(example.charAt(1), '.');

  return parseFloat(normalized);
}

const corpus = {
  '1.123': {
    expected: 1.123,
    locale: 'en-US'
  },
  '1,123': {
    expected: 1123,
    locale: 'en-US'
  },
  '2.123': {
    expected: 2123,
    locale: 'fr-FR'
  },
  '2,123': {
    expected: 2.123,
    locale: 'fr-FR'
  },
}


for (const candidate in corpus) {
  const {
    locale,
    expected
  } = corpus[candidate];
  const parsed = parseNumber(candidate, locale);

  console.log(`${ candidate } in ${ corpus[ candidate ].locale } == ${ expected }? ${ parsed === expected }`);
}

Their's obviously room for some optimization and caching but this works reliably in all languages.

Answer 4

Caveat: This won't work for numbers in scientific notation (like 1e3 for one thousand).

Remove anything that isn't a digit, decimal separator, or minus sign (-) (or optionally, a + if you want to allow a unary + on the number).

If you can assume that . is the decimal separator (it isn't in many parts of the world; keep reading), that might look like this:

function convertToFloat(str) {
    let body = str;
    let sign = "";
    const signMatch = /^\s*(-|\+)/.exec(str);
    // Or if you don't want to support unary +:
    // const signMatch = /^\s*(-)/.exec(str);
    if (signMatch) {
        body = str.substring(signMatch.index + 1);
        sign = signMatch[1];
    }
    const updatedBody = str.replace(/[^\d\.]/g, "");
    const num = parseFloat(sign + updatedBody);
    return num;
}

Live Example (I've added a fractional portion to the number just to show that working):

function convertToFloat(str) {
    let body = str;
    let sign = "";
    const signMatch = /^\s*(-|\+)/.exec(str);
    // Or if you don't want to support unary +:
    // const signMatch = /^\s*(-)/.exec(str);
    if (signMatch) {
        body = str.substring(signMatch.index + 1);
        sign = signMatch[1];
    }
    const updatedBody = str.replace(/[^\d\.]/g, "");
    const num = parseFloat(sign + updatedBody);
    return num;
}

console.log(convertToFloat("2,299.23"));

If you want to support locales where . isn't the decimal separator (there are many), you can detect the decimal separator and use the detected one in your regular expression. Here's an example function for finding the decimal separator:

function findDecimalSeparator() {
    const num = 1.2;
    if (typeof Intl === "object" && Intl && Intl.NumberFormat) {
        // I'm surprised it's this much of a pain and am hoping I'm missing
        // something in the API
        const formatter = new Intl.NumberFormat();
        const parts = formatter.formatToParts(num);
        const decimal = parts.find(({ type }) => type === "decimal").value;
        return decimal;
    }
    // Doesn't support `Intl.NumberFormat`, fall back to dodgy means
    const str = num.toLocaleString();
    const parts = /1(\D+)2/.exec(str);
    return parts[1];
}

Then convertToFloat looks like:

const decimal = findDecimalSeparator();
function convertToFloat(str) {
    let body = str;
    let sign = "";
    const signMatch = /^\s*(-|\+)/.exec(str);
    // Or if you don't want to support unary +:
    // const signMatch = /^\s*(-)/.exec(str);
    if (signMatch) {
        body = str.substring(signMatch.index + 1);
        sign = signMatch[1];
    }
    const rex = new RegExp(`${escapeRegex(decimal)}|-|\\+|\\D`, "g");
    const updatedBody = body.replace(
        rex,
        (match) => match === decimal ? "." : ""
    );
    const num = parseFloat(sign + updatedBody);
    return num;
}

Live Example:

const decimal = findDecimalSeparator();

function findDecimalSeparator() {
    const num = 1.2;
    if (typeof Intl === "object" && Intl && Intl.NumberFormat) {
        // I'm surprised it's this much of a pain and am hoping I'm missing
        // something in the API
        const formatter = new Intl.NumberFormat();
        const parts = formatter.formatToParts(num);
        const decimal = parts.find(({ type }) => type === "decimal").value;
        return decimal;
    }
    // Doesn't support `Intl.NumberFormat`, fall back to dodgy means
    const str = num.toLocaleString();
    const parts = /1(\D+)2/.exec(str);
    return parts[1];
}

function escapeRegex(string) {
    return string.replace(/[/\-\\^$*+?.()|[\]{}]/g, "\\$&");
}

function convertToFloat(str) {
    let body = str;
    let sign = "";
    const signMatch = /^\s*(-|\+)/.exec(str);
    // Or if you don't want to support unary +:
    // const signMatch = /^\s*(-)/.exec(str);
    if (signMatch) {
        body = str.substring(signMatch.index + 1);
        sign = signMatch[1];
    }
    const rex = new RegExp(`${escapeRegex(decimal)}|-|\\+|\\D`, "g");
    const updatedBody = body.replace(
        rex,
        (match) => match === decimal ? "." : ""
    );
    const num = parseFloat(sign + updatedBody);
    return num;
}

function gid(id) {
    const element = document.getElementById(id);
    if (!element) {
        throw new Error(`No element found for ID ${JSON.stringify(id)}`);
    }
    return element;
}

function onClick(id, handler) {
    gid(id).addEventListener("click", handler);
}

onClick("convert", () => {
    const str = gid("num").value;
    const num = convertToFloat(str);
    console.log(`${JSON.stringify(str)} => ${num}`);
});

<div>Enter a number using your locale's grouping and decimal separators, optionally prefaced with a minus sign (<code>-</code>) or plus sign (<code>+</code>):</div>
<input type="text" id="num" value="-123">
<input type="button" id="convert" value="Convert">

Answer 5

Usually you should consider to use input fields which don't allow free text input for numeric values. But there might be cases, when you need to guess the input format. For example 1.234,56 in Germany means 1,234.56 in US. See https://salesforce.stackexchange.com/a/21404 for a list of countries which use comma as decimal.

I use the following function to do a best guess and strip off all non-numeric characters:

function parseNumber(strg) {
    var strg = strg || "";
    var decimal = '.';
    strg = strg.replace(/[^0-9$.,]/g, '');
    if(strg.indexOf(',') > strg.indexOf('.')) decimal = ',';
    if((strg.match(new RegExp("\\" + decimal,"g")) || []).length > 1) decimal="";
    if (decimal != "" && (strg.length - strg.indexOf(decimal) - 1 == 3) && strg.indexOf("0" + decimal)!==0) decimal = "";
    strg = strg.replace(new RegExp("[^0-9$" + decimal + "]","g"), "");
    strg = strg.replace(',', '.');
    return parseFloat(strg);
}   

Try it here: https://plnkr.co/edit/9p5Y6H?p=preview

Examples:

1.234,56 € => 1234.56
1,234.56USD => 1234.56
1,234,567€ => 1234567
1.234.567 => 1234567
1,234.567 => 1234.567
1.234 => 1234 // might be wrong - best guess
1,234 => 1234 // might be wrong - best guess
1.2345 => 1.2345
0,123 => 0.123

The function has one weak point: It is not possible to guess the format if you have 1,123 or 1.123 - because depending on the locale format both might be a comma or a thousands-separator. In this special case the function will treat separator as a thousands-separator and return 1123.

Answer 6

It's baffling that they included a toLocaleString but not a parse method. At least toLocaleString without arguments is well supported in IE6+.

For a i18n solution, I came up with this:

First detect the user's locale decimal separator:

var decimalSeparator = 1.1;
decimalSeparator = decimalSeparator.toLocaleString().substring(1, 2);

Then normalize the number if there's more than one decimal separator in the String:

var pattern = "([" + decimalSeparator + "])(?=.*\\1)";separator
var formatted = valor.replace(new RegExp(pattern, "g"), "");

Finally, remove anything that is not a number or a decimal separator:

formatted = formatted.replace(new RegExp("[^0-9" + decimalSeparator + "]", "g"), '');
return Number(formatted.replace(decimalSeparator, "."));

Answer 7

Number("2,299.00".split(',').join(''));   // 2299

The split function splits the string into an array using "," as a separator and returns an array.
The join function joins the elements of the array returned from the split function.
The Number() function converts the joined string to a number.

Answer 8

If you want to avoid the problem that David Meister posted and you are sure about the number of decimal places, you can replace all dots and commas and divide by 100, ex.:

var value = "2,299.00";
var amount = parseFloat(value.replace(/"|\,|\./g, ''))/100;

or if you have 3 decimals

var value = "2,299.001";
var amount = parseFloat(value.replace(/"|\,|\./g, ''))/1000;

It's up to you if you want to use parseInt, parseFloat or Number. Also If you want to keep the number of decimal places you can use the function .toFixed(...).

Answer 9

or try this shorter approach:

const myNum =  +('2,299.00'.replace(",",""));

If you have several commas use Regex:

const myNum =  +('2,022,233,988.55'.replace(/,/g,""));
// -> myNum = 2022233988.55

Here was my case in an array (for similar use case):

To get the sum of this array:

const numbers = ["11", "7", "15/25", "18/5", "12", "16/25"]

By using parseFloat I would lose the decimals so to get the exact sum I had to first replace the forward slash with dot, then convert the strings to actual numbers.

So:

const currectNumbers = numbers.map(num => +(num.replace("/",".")))

// or the longer approach:
const currectNumbers = numbers
.map(num => num.replace("/","."))
.map(num => parseFloat(num));

This will give me the desired array to be used in reduce method:

currectNumbers = [ 11, 7, 15.25, 18.5, 12, 16.25]

Answer 10

All of these answers fail if you have a number in the millions.

3,456,789 would simply return 3456 with the replace method.

The most correct answer for simply removing the commas would have to be.

var number = '3,456,789.12';
number.split(',').join('');
/* number now equips 3456789.12 */
parseFloat(number);

Or simply written.

number = parseFloat(number.split(',').join(''));

Answer 11

This converts a number in whatever locale to normal number. Works for decimals points too:

function numberFromLocaleString(stringValue, locale){
    var parts = Number(1111.11).toLocaleString(locale).replace(/\d+/g,'').split('');
    if (stringValue === null)
        return null;
    if (parts.length==1) {
        parts.unshift('');
    }   
    return Number(String(stringValue).replace(new RegExp(parts[0].replace(/\s/g,' '),'g'), '').replace(parts[1],"."));
}

//Use default browser locale
numberFromLocaleString("1,223,333.567") //1223333.567

//Use specific locale
numberFromLocaleString("1 223 333,567", "ru") //1223333.567

Answer 12

const parseLocaleNumber = strNum => {
    const decSep = (1.1).toLocaleString().substring(1, 2);
    const formatted = strNum
        .replace(new RegExp(`([${decSep}])(?=.*\\1)`, 'g'), '')
        .replace(new RegExp(`[^0-9${decSep}]`, 'g'), '');
    return Number(formatted.replace(decSep, '.'));
};

Answer 13

With this function you will be able to format values in multiple formats like 1.234,56 and 1,234.56, and even with errors like 1.234.56 and 1,234,56

/**
 * @param {string} value: value to convert
 * @param {bool} coerce: force float return or NaN
 */
function parseFloatFromString(value, coerce) {
    value = String(value).trim();

    if ('' === value) {
        return value;
    }

    // check if the string can be converted to float as-is
    var parsed = parseFloat(value);
    if (String(parsed) === value) {
        return fixDecimals(parsed, 2);
    }

    // replace arabic numbers by latin
    value = value
    // arabic
    .replace(/[\u0660-\u0669]/g, function(d) {
        return d.charCodeAt(0) - 1632;
    })

    // persian
    .replace(/[\u06F0-\u06F9]/g, function(d) {
        return d.charCodeAt(0) - 1776;
    });

    // remove all non-digit characters
    var split = value.split(/[^\dE-]+/);

    if (1 === split.length) {
        // there's no decimal part
        return fixDecimals(parseFloat(value), 2);
    }

    for (var i = 0; i < split.length; i++) {
        if ('' === split[i]) {
            return coerce ? fixDecimals(parseFloat(0), 2) : NaN;
        }
    }

    // use the last part as decimal
    var decimal = split.pop();

    // reconstruct the number using dot as decimal separator
    return fixDecimals(parseFloat(split.join('') +  '.' + decimal), 2);
}

function fixDecimals(num, precision) {
    return (Math.floor(num * 100) / 100).toFixed(precision);
}

parseFloatFromString('1.234,56')
"1234.56"
parseFloatFromString('1,234.56')
"1234.56"
parseFloatFromString('1.234.56')
"1234.56"
parseFloatFromString('1,234,56')
"1234.56"

Answer 14

Based on many great architects here, I've simplified it a bit.

I prefer to use Intl.NumberFormat(undefined) to make it use the best fit mechanism.

If the user, like me, has a Danish keyboard, but prefer the Mac to be english, this helps: if (Number.isNaN(normalized)) return Number(value.replace(',', '.'));

If this is used in a form, I found that I should use inputMode="numeric" rather than type="number".

function parseNumber(value, locales = undefined) {
  if (typeof value !== 'string') return value;
  const example = Intl.NumberFormat(locales).format('1.1');
  const normalized = Number(value.replace(example.charAt(1), '.'));
  if (Number.isNaN(normalized)) return Number(value.replace(',', '.'));
  return normalized;
}

/* test */

const tests = [
  {
    locale: 'en-US',
    candidate: 1.123,
    expected: 1.123,
  },
  {
    locale: 'en-US',
    candidate: '1.123',
    expected: 1.123,
  },
  {
    locale: 'fr-FR',
    candidate: '33.123',
    expected: 33.123,
  },
  {
    locale: 'fr-FR',
    candidate: '33,123',
    expected: 33.123,
  },
  {
    locale: 'da-DK',
    candidate: '45.123',
    expected: 45.123,
  },
  {
    locale: 'da-DK',
    candidate: '45,123',
    expected: 45.123,
  },
  {
    locale: 'en-US',
    candidate: '0.123',
    expected: 0.123,
  },
  {
    locale: undefined,
    candidate: '0,123',
    expected: 0.123,
  },
];

tests.forEach(({ locale, candidate, expected }) => {
  const parsed = parseNumber(candidate, locale);
  console.log(`${candidate} as ${typeof candidate} in ${locale}: ${parsed} === ${expected}? ${parsed === expected}`);
});

Answer 15

If you want a l10n answer do it this way. Example uses currency, but you don't need that. Intl library will need to be polyfilled if you have to support older browsers.

var value = "2,299.00";
var currencyId = "USD";
var nf = new Intl.NumberFormat(undefined, {style:'currency', currency: currencyId, minimumFractionDigits: 2});

value = nf.format(value.replace(/,/g, ""));

Answer 16

If you have a small set of locales to support you'd probably be better off by just hardcoding a couple of simple rules:

function parseNumber(str, locale) {
  let radix = ',';
  if (locale.match(/(en|th)([-_].+)?/)) {
    radix = '.';
  }
  return Number(str
    .replace(new RegExp('[^\\d\\' + radix + ']', 'g'), '')
    .replace(radix, '.'));
}