parseFloat() global function JS Home  <<  JS Reference  <<  parseFloat()

Global function that converts a string to a float.


Parses a string argument (converting it to a string first if required) and attempts to return a floating point number.


Signature Description
parseFloat(string)Global function that converts a string to a float.


Parameter Description
stringThe string value you want to parse.
  • Leading and trailing spaces are allowed and will be ignored.
  • If the first non space character is not a sign (+ or -), numeral (0-9), decimal point or an exponent, and cannot be converted to a number, parseFloat returns NaN.
  • While parsing after the first non space character if the function encounters a character other than a sign (+ or -), numeral (0-9), a decimal point, or an exponent, it returns the value up to that point and ignores that character and all subsequent characters.


Below are some examples of using the parseFloat() function.

// Parsing string to floats.
var parsedValues = new Array(6);

parsedValues[0] = parseFloat('17'); // integer
parsedValues[1] = parseFloat('17.2345'); // valid 
parsedValues[2] = parseFloat('-17.2345'); // negative 
parsedValues[3] = parseFloat('  17.2345   '); // within spaces
parsedValues[4] = parseFloat('17.2345ignored'); // ignore non decimal suffix
parsedValues[5] = parseFloat('abcdef'); // invalid


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Related Tutorials

JavaScript Intermediate Tutorials - Lesson 6 - More Maths Functions