iOS 18 Control Center Sizing for Third-Party Apps

With iOS 18, Apple allows third-party developers to integrate their apps directly into the redesigned Control Center using the WidgetKit Controls API. However, developers cannot create arbitrary, custom sizing options or unique aspect ratios for their toggles. Instead, third-party controls must adhere to Apple’s predefined grid templates, with resizing handled primarily by the end user rather than the developer.

The Fixed Grid System

Apple redesigned the Control Center in iOS 18 around a standardized 4x8 grid per page. All interactive elements—whether built by Apple or external developers—are locked to this layout structure to maintain visual consistency and predictable touch targets across the system.

Third-party controls support three primary standardized sizes:

• Small (1x1): A single circular button displaying an icon and basic state tinting.
• Medium (2x1): A wider rectangular pill displaying an icon, title, and current status subtitle.
• Large (2x2): A larger block used for more prominent actions or complex state visualizers.

Developer Implementation via WidgetKit

Developers implement actions using types such as ControlWidgetToggle and ControlWidgetButton. The API handles layout and appearance programmatically, meaning developers do not design freeform custom user interfaces or supply bespoke dimensions.

Instead, developers provide the underlying metadata, including:

• A SF Symbol icon representing the action.
• Text labels (title and dynamic state description).
• An execution intent via the App Intents framework to run background code or open the app.
• A tint color to indicate whether the toggle is active or inactive.

When a developer writes a ControlWidget, the system automatically scales and reformats that metadata to fit the standard sizes supported by the control type. Developers cannot alter margins, pad dimensions, or create asymmetrical shapes outside of Apple's system-rendered controls.

User-Driven Resizing

The decision to scale a control lies entirely with the user. In iOS 18, entering the Control Center edit mode reveals an adjustment handle on supported controls. Users can drag this handle to resize a control between available standard formats (such as expanding a 1x1 toggle into a 2x1 pill).

If a control only supports specific representations—such as a single-action trigger that only makes sense as a 1x1 icon—the system limits resizing options accordingly, but developers cannot introduce non-standard sizes into that framework.