diff --git a/packages/utils/src/loader/custom.ts b/packages/utils/src/loader/custom.ts
index cc3ac19..5ba8c90 100644
--- a/packages/utils/src/loader/custom.ts
+++ b/packages/utils/src/loader/custom.ts
@@ -1,3 +1,4 @@
+import type { Awaitable } from '@antfu/utils';
 import createDebugger from 'debug';
 import type { CustomIconLoader, InlineCollection } from './types';
 
@@ -7,7 +8,7 @@ export async function getCustomIcon(
 	custom: CustomIconLoader | InlineCollection,
 	collection: string,
 	icon: string,
-	scale = 1
+	transform?: (svg: string) => Awaitable<string>
 ): Promise<string | undefined> {
 	let result: string | undefined | null;
 
@@ -27,6 +28,6 @@ export async function getCustomIcon(
 		if (!result.startsWith('<svg ')) {
 			console.warn(`Custom icon "${icon}" in "${collection}" is not a valid SVG`);
 		}
-		return result.replace('<svg ', `<svg height="${scale}em" width="${scale}em" `);
+		return transform ? await transform(result) : result
 	}
 }