Unary negation (-)

Baseline Widely available

This feature is well established and works across many devices and browser versions. It's been available across browsers since July 2015.

The unary negation (-) operator precedes its operand and negates it.

Try it

const x = 4;
const y = -x;

console.log(y);
// Expected output: -4

const a = "4";
const b = -a;

console.log(b);
// Expected output: -4

Syntax

-x

Description

The - operator is overloaded for two types of operands: number and BigInt. It first coerces the operand to a numeric value and tests the type of it. It performs BigInt negation if the operand becomes a BigInt; otherwise, it performs number negation.

Examples

Negating numbers

const x = 3;
const y = -x;
// y is -3; x is 3

Negating non-numbers

The unary negation operator can convert a non-number into a number.

const x = "4";
const y = -x;

// y is -4

BigInts can be negated using the unary negation operator.

const x = 4n;
const y = -x;

// y is -4n

Specifications

Specification
ECMAScript® 2027 Language Specification # sec-unary-minus-operator

Browser compatibility

	Desktop					Mobile							Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`unary_negation`	1	12	1	3	1	18	4	10.1	1	1.0	4.4	1	1.0.0	1.0	0.10.0