# &-(_:_:) Returns the difference of the two given values, wrapping the result in case of any overflow. ``` static func &- (lhs: Self, rhs: Self) -> Self ``` ## Parameters `lhs` A numeric value. `rhs` The value to subtract from `lhs`. ## Discussion The overflow subtraction operator (`&-`) discards any bits that overflow the fixed width of the integer type. In the following example, the difference of `10` and `21` is less than zero, the minimum representable `UInt` value, so the result is the partial value after discarding the overflowing bits. ``` let x: UInt8 = 21 &- 10 // x == 11 let y: UInt8 = 10 &- 21 // y == 245 (after overflow) ``` For more about arithmetic with overflow operators, see [Overflow Operators](https://docs.swift.org/swift-book/LanguageGuide/AdvancedOperators.html#ID37) in *[The Swift Programming Language](https://docs.swift.org/swift-book/)*. --- 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)