Number() constructor

The Number() constructor creates a Number object. When called instead as a function, it performs type conversion to a primitive number, which is usually more useful.


new Number(value)

Note: Number() can be called with or without new, but with different effects. See Return value.



The numeric value of the object being created.

Return value

When Number is called as a constructor (with new), it creates a Number object, which is not a primitive.

When Number is called as a function, it coerces the parameter to a number primitive. If the value can't be converted, it returns NaN.

Warning: You should rarely find yourself using Number as a constructor.


Creating Number objects

const a = new Number('123'); // a === 123 is false
const b = Number('123');     // b === 123 is true
a instanceof Number;         // is true
b instanceof Number;         // is false
typeof a // "object"
typeof b // "number"


ECMAScript Language Specification
# sec-number-constructor

Browser compatibility

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See also