Last Updated : 11 Jul, 2025
TheparseInt method parses a value as a string and returns the first integer. It accepts a string argument and optional radix parameter, defining the numeral system base. This method is commonly used for converting string representations of numbers into integers.
Example:
The method takes two parameters: the string to be parsed and the radix (optional, default is 10).
2 = binary, 8 = octal, 10 = decimal, 16 = hexadecimal.
Syntax
parseInt(Value, radix);
Parameters
Return value
It returns a number and if the first character can't be converted to a number then the function returns NaN. It returns a number parsed up to that point where it encounters a character that is not a number in the specified radix(base).
Example 1: Parsing float value
Here, we are using the parseInt() method to parse the given float value.
javascript
let v1 = parseInt("3.14");
console.log('Using parseInt("3.14") = '+ v1);
Using parseInt("3.14") = 3
Example 2: Parsing value with given radix
Here, we will also mention radix with the number.
javascript
// Base 10
a = parseInt("100", 10);
console.log('parseInt("100",10) = ' +
a);
// Base 8
b = parseInt("8", 8);
console.log('parseInt("8",8) = ' +
b);
// Base 8
c = parseInt("15", 8);
console.log('parseInt("15",8) = ' +
c);
// Base 16
d = parseInt("16", 16);
console.log('parseInt("16",16) = ' +
d);
// Leading and trailing spaces are ignored
// in parseInt() function
e = parseInt(" 100 ");
console.log('parseInt(" 100 ") = ' +
e);
// Base 16(hexadecimal)
f = parseInt("0x16");
console.log('parseInt("0x16") = ' +
f);
parseInt("100",10) = 100
parseInt("8",8) = NaN
parseInt("15",8) = 13
parseInt("16",16) = 22
parseInt(" 100 ") = 100
parseInt("0x16") = 22
We have a complete list of JavaScript Number constructor, properties, and methods list, to know more about the numbers please go through that article.
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