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

js
-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

js
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.

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

// y is -4

BigInts can be negated using the unary negation operator.

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

// y is -4n

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-unary-minus-operator

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
Unary negation (-)

Legend

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Full support
Full support

See also