diff --git a/src/panels/lovelace/create-element/create-element-base.ts b/src/panels/lovelace/create-element/create-element-base.ts
index 8a1482e43e..4556efe509 100644
--- a/src/panels/lovelace/create-element/create-element-base.ts
+++ b/src/panels/lovelace/create-element/create-element-base.ts
@@ -154,7 +154,7 @@ const _lazyCreate = <T extends keyof CreateElementConfigTypes>(
 
 const _getCustomTag = (type: string) =>
   type.startsWith(CUSTOM_TYPE_PREFIX)
-    ? type.substr(CUSTOM_TYPE_PREFIX.length)
+    ? type.slice(CUSTOM_TYPE_PREFIX.length)
     : undefined;
 
 export const createLovelaceElement = <T extends keyof CreateElementConfigTypes>(
diff --git a/src/panels/lovelace/editor/get-card-documentation-url.ts b/src/panels/lovelace/editor/get-card-documentation-url.ts
index e810f6bb4f..7d01eb9419 100644
--- a/src/panels/lovelace/editor/get-card-documentation-url.ts
+++ b/src/panels/lovelace/editor/get-card-documentation-url.ts
@@ -10,7 +10,8 @@ export const getCardDocumentationURL = (
   type: string
 ): string | undefined => {
   if (type.startsWith(CUSTOM_TYPE_PREFIX)) {
-    return getCustomCardEntry(type)?.documentationURL;
+    return getCustomCardEntry(type.slice(CUSTOM_TYPE_PREFIX.length))
+      ?.documentationURL;
   }
 
   return `${documentationUrl(hass, "/lovelace/")}${type}`;