files/en-us/web/javascript/reference/global_objects/number/parsefloat/index.md

metadata

title: Number.parseFloat()
short-title: parseFloat()
slug: Web/JavaScript/Reference/Global_Objects/Number/parseFloat
page-type: javascript-static-method
browser-compat: javascript.builtins.Number.parseFloat
sidebar: jsref

The Number.parseFloat() static method parses an argument and returns a floating point number. If a number cannot be parsed from the argument, it returns {{jsxref("NaN")}}.

{{InteractiveExample("JavaScript Demo: Number.parseFloat()")}}

function circumference(r) {
  if (Number.isNaN(Number.parseFloat(r))) {
    return 0;
  }
  return parseFloat(r) * 2.0 * Math.PI;
}

console.log(circumference("4.567abcdefgh"));
// Expected output: 28.695307297889173

console.log(circumference("abcdefgh"));
// Expected output: 0

Syntax

Number.parseFloat(string)

Parameters

• string
  • : The value to parse, coerced to a string. Leading {{Glossary("whitespace")}} in this argument is ignored.

Return value

A floating point number parsed from the given string.

Or {{jsxref("NaN")}} when the first non-whitespace character cannot be converted to a number.

Examples

Number.parseFloat vs. parseFloat

This method has the same functionality as the global {{jsxref("parseFloat()")}} function:

Number.parseFloat === parseFloat; // true

Its purpose is modularization of globals.

See {{jsxref("parseFloat()")}} for more detail and examples.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Polyfill of Number.parseFloat in core-js
• es-shims polyfill of Number.parseFloat
• {{jsxref("Number")}}
• {{jsxref("parseFloat()")}}