diff --git a/app/javascript/mastodon/features/compose/util/counter.js b/app/javascript/mastodon/features/compose/util/counter.js
index 588a372c6..e6d2487c5 100644
--- a/app/javascript/mastodon/features/compose/util/counter.js
+++ b/app/javascript/mastodon/features/compose/util/counter.js
@@ -5,5 +5,5 @@ const urlPlaceholder = 'xxxxxxxxxxxxxxxxxxxxxxx';
 export function countableText(inputText) {
   return inputText
     .replace(urlRegex, urlPlaceholder)
-    .replace(/(?:^|[^\/\w])@(([a-z0-9_]+)@[a-z0-9\.\-]+)/ig, '@$2');
+    .replace(/(?:^|[^\/\w])@(([a-z0-9_]+)@[a-z0-9\.\-]+[a-z0-9]+)/ig, '@$2');
 };