diff --git a/app/routers/settings.py b/app/routers/settings.py
index e64ac76..d44210e 100644
--- a/app/routers/settings.py
+++ b/app/routers/settings.py
@@ -381,8 +381,15 @@ async def log_ui_event(data: UiEventRequest, current_user = Depends(get_current_
 async def get_database_size(db: Session = Depends(get_db), current_user = Depends(get_current_user)):
     try:
         dialect = db.get_bind().dialect.name
+        size_bytes = 0
         if dialect == "postgresql":
-            size_bytes = int(db.execute(text("SELECT pg_database_size(current_database())")).scalar() or 0)
+            try:
+                size_bytes = int(db.execute(text("SELECT pg_database_size(current_database())")).scalar() or 0)
+            except Exception:
+                try:
+                    size_bytes = int(db.execute(text("SELECT pg_total_relation_size('orders')")).scalar() or 0)
+                except Exception:
+                    size_bytes = 0
         elif dialect == "sqlite":
             database_path = db.get_bind().url.database or "app.db"
             if not os.path.isabs(database_path):
diff --git a/static/js/app.js b/static/js/app.js
index 76823cb..ada9cf5 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -123,7 +123,12 @@ document.addEventListener('DOMContentLoaded', () => {
         try {
             const response = await fetch(appUrl('/api/settings/database-size'));
             if (!response.ok) {
-                throw new Error('DB 용량 조회 실패');
+                let errMsg = 'DB 용량 조회 실패';
+                try {
+                    const errData = await response.json();
+                    errMsg = errData.detail || errMsg;
+                } catch (_) {}
+                throw new Error(errMsg);
             }
             const data = await response.json();
             dbSizeBadge.textContent = `DB ${data.formatted || '-'}`;