---
title: Math.imul()
short-title: imul()
slug: Web/JavaScript/Reference/Global_Objects/Math/imul
page-type: javascript-static-method
browser-compat: javascript.builtins.Math.imul
sidebar: jsref
---

The **`Math.imul()`** static method returns the result of the C-like 32-bit multiplication of the two parameters.

{{InteractiveExample("JavaScript Demo: Math.imul()")}}

```js interactive-example
console.log(Math.imul(3, 4));
// Expected output: 12

console.log(Math.imul(-5, 12));
// Expected output: -60

console.log(Math.imul(0xffffffff, 5));
// Expected output: -5

console.log(Math.imul(0xfffffffe, 5));
// Expected output: -10
```

## Syntax

```js-nolint
Math.imul(a, b)
```

### Parameters

- `a`
  - : First number.
- `b`
  - : Second number.

### Return value

The result of the C-like 32-bit multiplication of the given arguments.

## Description

`Math.imul()` allows for 32-bit integer multiplication with C-like semantics. This feature is useful for projects like [Emscripten](https://en.wikipedia.org/wiki/Emscripten).

Because `imul()` is a static method of `Math`, you always use it as `Math.imul()`, rather than as a method of a `Math` object you created (`Math` is not a constructor).

If you use normal JavaScript floating point numbers in `imul()`, you will experience a degrade in performance. This is because of the costly conversion from a floating point to an integer for multiplication, and then converting the multiplied integer back into a floating point. However, with [asm.js](/en-US/docs/Games/Tools/asm.js), which allows JIT-optimizers to more confidently use integers in JavaScript, multiplying two numbers stored internally as integers (which is only possible with asm.js) with `imul()` could be potentially more performant.

## Examples

### Using Math.imul()

```js
Math.imul(2, 4); // 8
Math.imul(-1, 8); // -8
Math.imul(-2, -2); // 4
Math.imul(0xffffffff, 5); // -5
Math.imul(0xfffffffe, 5); // -10
```

## Specifications

{{Specifications}}

## Browser compatibility

{{Compat}}

## See also

- [Polyfill of `Math.imul` in `core-js`](https://github.com/zloirock/core-js#ecmascript-math)
- [es-shims polyfill of `Math.imul`](https://www.npmjs.com/package/math.imul)
- [Emscripten](https://en.wikipedia.org/wiki/Emscripten) on Wikipedia