JavaScript (ES2026) reference · JSON and Global Functions

JavaScript parseFloat() Function

Parse a decimal number from the start of a string, stopping at the first character that can't be part of it.

JavaScript (ES2026) Since ES1

Create a free account to save this page, take notes and track your progress. Sign in

Syntax

parseFloat(string)

Parameter	Description
`string`	The text to parse.

A number or NaN.

Parse decimalsTry it yourself

console.log(parseFloat("3.5kg"), parseFloat("1e3"), parseFloat("kg3.5"));

Output

3.5 1000 NaN

Comma decimals need convertingTry it yourself

console.log(parseFloat("1,5"), Number("1,5".replace(",", ".")));

Output

1 1.5

Version	Change
JavaScript ES1	Added

Number.parseFloat() · Parse a decimal number from the start of a string, ignoring trailing text. Same as the global parseFloat().
parseInt() · Parse an integer from the start of a string in a given base. Always pass the radix, e.g. parseInt("08", 10).
JavaScript Type Conversion · tutorial