diff --git a/app/static/js/app.js b/app/static/js/app.js
index 75eb5d0..877b446 100644
--- a/app/static/js/app.js
+++ b/app/static/js/app.js
@@ -2865,14 +2865,15 @@ function formatTime(timestamp) {
         return date.toLocaleDateString() + ' ' + date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
     }
 
-    // When viewing live messages, use relative time
+    // When viewing live messages, compare calendar dates
     const now = new Date();
-    const diffDays = Math.floor((now - date) / (1000 * 60 * 60 * 24));
+    const yesterday = new Date(now);
+    yesterday.setDate(yesterday.getDate() - 1);
 
-    if (diffDays === 0) {
+    if (date.toDateString() === now.toDateString()) {
         // Today - show time only
         return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
-    } else if (diffDays === 1) {
+    } else if (date.toDateString() === yesterday.toDateString()) {
         // Yesterday
         return 'Yesterday ' + date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
     } else {
diff --git a/app/static/js/dm.js b/app/static/js/dm.js
index 0360af9..7caf536 100644
--- a/app/static/js/dm.js
+++ b/app/static/js/dm.js
@@ -1662,10 +1662,13 @@ function formatTime(timestamp) {
 
     const date = new Date(timestamp * 1000);
     const now = new Date();
-    const isToday = date.toDateString() === now.toDateString();
+    const yesterday = new Date(now);
+    yesterday.setDate(yesterday.getDate() - 1);
 
-    if (isToday) {
+    if (date.toDateString() === now.toDateString()) {
         return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
+    } else if (date.toDateString() === yesterday.toDateString()) {
+        return 'Yesterday ' + date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
     } else {
         return date.toLocaleDateString([], { month: 'short', day: 'numeric' }) +
                ' ' + date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });