# -(_:_:) Subtracts one value from another and produces their difference. ``` static func - (lhs: Int8, rhs: Int8) -> Int8 ``` ## Parameters `lhs` A numeric value. `rhs` The value to subtract from `lhs`. ## Discussion The subtraction operator (`-`) calculates the difference of its two arguments. For example: ``` 8 - 3 // 5 -10 - 5 // -15 100 - -5 // 105 10.5 - 100.0 // -89.5 ``` You cannot use `-` with arguments of different types. To subtract values of different types, convert one of the values to the other value’s type. ``` let x: UInt8 = 21 let y: UInt = 1000000 y - UInt(x) // 999979 ``` The difference of the two arguments must be representable in the arguments’ type. In the following example, the result of `21 - 50` is less than zero, the minimum representable `UInt8` value: ``` x - 50 // Overflow error ``` > Note: Overflow checking is not performed in `-Ounchecked` builds. If you want to opt out of overflow checking and wrap the result in case of any overflow, use the overflow subtraction operator (`&-`). ``` x &- 50 // 227 ``` --- 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)