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Number.parseFloat() - JavaScript | MDN

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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 September 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.

In this article

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® 2027 Language Specification
# sec-number.parsefloat

Browser compatibility

Enable JavaScript to view this browser compatibility table.

See also

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This page was last modified on Jul 10, 2025 by MDN contributors.

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Standard built-in objects
Number
Constructor
1. Number()
Static methods
Static properties
Instance methods
Inheritance
Object/Function
Static methods
Static properties
Instance methods
Instance properties
1. __proto__
2. constructor