# +(_:_:) Adds two values and produces their sum. ``` static func + (lhs: Int, rhs: Int) -> Int ``` ## Parameters `lhs` The first value to add. `rhs` The second value to add. ## Discussion The addition operator (`+`) calculates the sum of its two arguments. For example: ``` 1 + 2 // 3 -10 + 15 // 5 -15 + -5 // -20 21.5 + 3.25 // 24.75 ``` You cannot use `+` with arguments of different types. To add values of different types, convert one of the values to the other value’s type. ``` let x: Int8 = 21 let y: Int = 1000000 Int(x) + y // 1000021 ``` The sum of the two arguments must be representable in the arguments’ type. In the following example, the result of `21 + 120` is greater than the maximum representable `Int8` value: ``` x + 120 // 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 addition operator (`&+`). ``` x &+ 120 // -115 ``` --- 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)