# speed(by:duration:) Creates an action that changes how fast the node executes actions by a relative value. ``` class func speed(by speed: CGFloat, duration: TimeInterval) -> SKAction ``` ## Parameters `speed` The amount to add to the node’s speed. `duration` The duration of the animation. ## Return Value A new action object. ## Discussion When the action executes, the node’s [`speed`](/documentation/SpriteKit/SKNode/speed) property animates to the new value. This action is reversible; the reverse is created as if the following code is executed: ```swift let action = SKAction.speed(by: -speed, duration: sec) ``` --- 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)