How to convert a currency string to a double with Javascript?

Remove all non dot / digits:

var currency = "-$4,400.50";
var number = Number(currency.replace(/[^0-9.-]+/g,""));

Use a regex to remove the formating (dollar and comma), and use parseFloat to convert the string to a floating point number.`

var currency = "$1,100.00";
currency.replace(/[$,]+/g,"");
var result = parseFloat(currency) + .05;

You can try this

var str = "$1,112.12";
str = str.replace(",", "");
str = str.replace("$", "");
console.log(parseFloat(str));

For anyone looking for a solution in 2021 you can use Currency.js.

After much research this was the most reliable method I found for production, I didn't have any issues so far. In addition it's very active on Github.

currency(123);      // 123.00
currency(1.23);     // 1.23
currency("1.23")    // 1.23
currency("$12.30")  // 12.30

var value = currency("123.45");
currency(value);    // 123.45

typescript

import currency from "currency.js";

currency("$12.30").value;    // 12.30

let thousands_seps = '.';
let decimal_sep = ',';

let sanitizeValue = "R$ 2.530,55".replace(thousands_seps,'')
                         .replace(decimal_sep,'.')
                         .replace(/[^0-9.-]+/, '');

// Converting to float
// Result 2530.55
let stringToFloat = parseFloat(sanitizeValue);


// Formatting for currency: "R$ 2.530,55"
// BRL in this case
let floatTocurrency = Number(stringToFloat).toLocaleString('pt-BR', {style: 'currency', currency: 'BRL'});

// Output
console.log(stringToFloat, floatTocurrency);

I know you've found a solution to your question, I just wanted to recommend that maybe you look at the following more extensive jQuery plugin for International Number Formats:

International Number Formatter

How about simply

Number(currency.replace(/[^0-9-]+/g,""))/100;

Works with all currencies and locales. replaces all non-numeric chars (you can have €50.000,00 or $50,000.00) input must have 2 decimal places

For currencies that use the ',' separator mentioned by Quethzel Diaz

Currency is in Brazilian.

var currency_br = "R$ 1.343,45";
currency_br = currency_br.replace('.', "").replace(',', '.');
var number_formated = Number(currency_br.replace(/[^0-9.-]+/g,""));

var parseCurrency = function (e) {
    if (typeof (e) === 'number') return e;
    if (typeof (e) === 'string') {
        var str = e.trim();
        var value = Number(e.replace(/[^0-9.-]+/g, ""));
        return str.startsWith('(') && str.endsWith(')') ? -value: value;
    }

    return e;
} 

This worked for me and covers most edge cases :)

function toFloat(num) {
  const cleanStr = String(num).replace(/[^0-9.,]/g, '');
  let dotPos = cleanStr.indexOf('.');
  let commaPos = cleanStr.indexOf(',');

  if (dotPos < 0) dotPos = 0;

  if (commaPos < 0) commaPos = 0;

  const dotSplit = cleanStr.split('.');
  const commaSplit = cleanStr.split(',');

  const isDecimalDot = dotPos
    && (
      (commaPos && dotPos > commaPos)
      || (!commaPos && dotSplit[dotSplit.length - 1].length === 2)
    );

  const isDecimalComma = commaPos
    && (
      (dotPos && dotPos < commaPos)
      || (!dotPos && commaSplit[commaSplit.length - 1].length === 2)
    );

  let integerPart = cleanStr;
  let decimalPart = '0';
  if (isDecimalComma) {
    integerPart = commaSplit[0];
    decimalPart = commaSplit[1];
  }
  if (isDecimalDot) {
    integerPart = dotSplit[0];
    decimalPart = dotSplit[1];
  }

  return parseFloat(
    `${integerPart.replace(/[^0-9]/g, '')}.${decimalPart.replace(/[^0-9]/g, '')}`,
  );
}

toFloat('USD 1,500.00'); // 1500
toFloat('USD 1,500'); // 1500
toFloat('USD 500.00'); // 500
toFloat('USD 500'); // 500

toFloat('EUR 1.500,00'); // 1500
toFloat('EUR 1.500'); // 1500
toFloat('EUR 500,00'); // 500
toFloat('EUR 500'); // 500

Here's a simple function -

function getNumberFromCurrency(currency) {
  return Number(currency.replace(/[$,]/g,''))
}

console.log(getNumberFromCurrency('$1,000,000.99')) // 1000000.99

Such a headache and so less consideration to other cultures for nothing...

here it is folks:

let floatPrice = parseFloat(price.replace(/(,|\.)([0-9]{3})/g,'$2').replace(/(,|\.)/,'.'));

as simple as that.

This function should work whichever the locale and currency settings :

function getNumPrice(price, decimalpoint) {
    var p = price.split(decimalpoint);
    for (var i=0;i<p.length;i++) p[i] = p[i].replace(/\D/g,'');
    return p.join('.');
}

This assumes you know the decimal point character (in my case the locale is set from PHP, so I get it with <?php echo cms_function_to_get_decimal_point(); ?>).