diff --git a/plugins/chat/assets/stylesheets/desktop/chat-index-full-page.scss b/plugins/chat/assets/stylesheets/desktop/chat-index-full-page.scss
index a175d8779dd..0de8658191d 100644
--- a/plugins/chat/assets/stylesheets/desktop/chat-index-full-page.scss
+++ b/plugins/chat/assets/stylesheets/desktop/chat-index-full-page.scss
@@ -1,7 +1,7 @@
 .has-full-page-chat:not(.discourse-sidebar) {
   .full-page-chat {
     .channels-list {
-      height: 100%;
+      height: calc(100vh - var(--header-offset));
       border-right: 1px solid var(--primary-low);
       background: var(--primary-very-low);