Bitwise NOT (~)

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 bitwise NOT (~) operator returns a number or BigInt whose binary representation has a 1 in each bit position for which the corresponding bit of the operand is 0, and a 0 otherwise.

Try it

const a = 5; // 00000000000000000000000000000101
const b = -3; // 11111111111111111111111111111101

console.log(~a); // 11111111111111111111111111111010
// Expected output: -6

console.log(~b); // 00000000000000000000000000000010
// Expected output: 2

Syntax

js
~x

Description

The ~ operator is overloaded for two types of operands: number and BigInt. For numbers, the operator returns a 32-bit integer. For BigInts, the operator returns a BigInt. It first coerces the operand to a numeric value and tests the type of it. It performs BigInt NOT if the operand becomes a BigInt; otherwise, it converts the operand to a 32-bit integer and performs number bitwise NOT.

The operator operates on the operands' bit representations in two's complement. The operator is applied to each bit, and the result is constructed bitwise.

The truth table for the NOT operation is:

x NOT x
0 1
1 0
 9 (base 10) = 00000000000000000000000000001001 (base 2)
               --------------------------------
~9 (base 10) = 11111111111111111111111111110110 (base 2) = -10 (base 10)

Numbers with more than 32 bits get their most significant bits discarded. For example, the following integer with more than 32 bits will be converted to a 32-bit integer:

Before: 11100110111110100000000000000110000000000001
After:              10100000000000000110000000000001

For BigInts, there's no truncation. Conceptually, understand positive BigInts as having an infinite number of leading 0 bits, and negative BigInts having an infinite number of leading 1 bits.

Bitwise NOTing any 32-bit integer x yields -(x + 1). For example, ~-5 yields 4.

Bitwise NOTing any number x twice returns x converted to a 32-bit integer. Do not use ~~x to truncate numbers to integers; use Math.trunc() instead. Due to using 32-bit representation for numbers, both ~-1 and ~4294967295 (232 - 1) result in 0.

Examples

Using bitwise NOT

js
~0; // -1
~-1; // 0
~1; // -2

~0n; // -1n
~4294967295n; // -4294967296n

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-bitwise-not-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
Bitwise NOT (~a)

Legend

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Full support
Full support

See also