# sizeThatFits(_:) Asks the view to calculate and return the size that best fits the specified size. ``` func sizeThatFits(_ size: CGSize) -> CGSize ``` ## Parameters `size` The size for which the view should calculate its best-fitting size. ## Return Value A new size that fits the receiver’s subviews. ## Discussion The default implementation of this method returns the existing size of the view. Subclasses can override this method to return a custom value based on the desired layout of any subviews. For example, a [`UISwitch`](/documentation/UIKit/UISwitch) object returns a fixed size value that represents the standard size of a switch view, and a [`UIImageView`](/documentation/UIKit/UIImageView) object returns the size of the image it is currently displaying. This method does not resize the receiver. ## See Also [`frame`](/documentation/UIKit/UIView/frame) The frame rectangle, which describes the view’s location and size in its superview’s coordinate system. [`bounds`](/documentation/UIKit/UIView/bounds) The bounds rectangle, which describes the view’s location and size in its own coordinate system. --- 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)