diff --git a/app.py b/app.py
index 622adfd..20c6bb2 100644
--- a/app.py
+++ b/app.py
@@ -728,12 +728,26 @@ def prompt_delete(prompt_id: int):
     return HTMLResponse("<meta http-equiv='refresh' content='0; url=/prompts'>")
 
 
+def _parse_utcish(ts: Optional[str]) -> Optional[datetime]:
+    if not ts:
+        return None
+    try:
+        return datetime.fromisoformat(str(ts).replace("Z", "+00:00")).replace(tzinfo=None)
+    except Exception:
+        try:
+            return datetime.fromisoformat(str(ts))
+        except Exception:
+            return None
+
+
 def _fmt_elapsed(start_iso: Optional[str], end_iso: Optional[str] = None) -> str:
-    if not start_iso:
+    s = _parse_utcish(start_iso)
+    if not s:
         return "-"
     try:
-        s = datetime.fromisoformat(start_iso)
-        e = datetime.fromisoformat(end_iso) if end_iso else datetime.now()
+        e = _parse_utcish(end_iso) if end_iso else datetime.utcnow()
+        if not e:
+            e = datetime.utcnow()
         sec = max(0, int((e - s).total_seconds()))
         if sec < 60:
             return f"{sec}s"
@@ -834,10 +848,16 @@ def jobs_page(queued: Optional[int] = None):
 <div id='jobs-status' class='hint'>Live-Update aktiv …</div>
 <div id='jobs-root'>{pre}</div>
 <script>
+function parseUtcish(ts) {{
+  if(!ts) return NaN;
+  const hasZone = /Z$|[+-]\d\d:\d\d$/.test(ts);
+  return Date.parse(hasZone ? ts : (ts + 'Z')); // DB stores UTC without suffix
+}}
 function since(ts, endTs=null) {{
   if(!ts) return '-';
-  const end = endTs ? Date.parse(endTs) : Date.now();
-  const s = Math.max(0, Math.floor((end-Date.parse(ts))/1000));
+  const startMs = parseUtcish(ts);
+  const end = endTs ? parseUtcish(endTs) : Date.now();
+  const s = Math.max(0, Math.floor((end-startMs)/1000));
   if (s<60) return s+'s';
   const m = Math.floor(s/60); if (m<60) return m+'m '+(s%60)+'s';
   const h = Math.floor(m/60); return h+'h '+(m%60)+'m';