Number.parseFloat()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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 NaN.

Try it

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

js
Number.parseFloat(string)

Parameters

string

The value to parse, coerced to a string. Leading whitespace in this argument is ignored.

Return value

A floating point number parsed from the given string.

Or 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 parseFloat() function:

js
Number.parseFloat === parseFloat; // true

Its purpose is modularization of globals.

See parseFloat() for more detail and examples.

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-number.parsefloat

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
parseFloat

Legend

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Full support
Full support

See also