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.
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® 2026 Language Specification # sec-number.parsefloat |