# multipliedFullWidth(by:) Returns a tuple containing the high and low parts of the result of multiplying this value by the given value. ``` func multipliedFullWidth(by other: Int) -> (high: Int, low: Int.Magnitude) ``` ## Parameters `other` The value to multiply this value by. ## Return Value A tuple containing the high and low parts of the result of multiplying this value and `other`. ## Discussion Use this method to calculate the full result of a product that would otherwise overflow. Unlike traditional truncating multiplication, the `multipliedFullWidth(by:)` method returns a tuple containing both the `high` and `low` parts of the product of this value and `other`. The following example uses this method to multiply two `Int8` values that normally overflow when multiplied: ``` let x: Int8 = 48 let y: Int8 = -40 let result = x.multipliedFullWidth(by: y) // result.high == -8 // result.low == 128 ``` The product of `x` and `y` is `-1920`, which is too large to represent in an `Int8` instance. The `high` and `low` components of the `result` value represent `-1920` when concatenated to form a double-width integer; that is, using `result.high` as the high byte and `result.low` as the low byte of an `Int16` instance. ``` let z = Int16(result.high) << 8 | Int16(result.low) // z == -1920 ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)