diff --git a/src/pages/Feed.tsx b/src/pages/Feed.tsx
index c4e3e4b..15a8e40 100644
--- a/src/pages/Feed.tsx
+++ b/src/pages/Feed.tsx
@@ -316,8 +316,10 @@ export default function Feed() {
                     )}
                   </div>
                   <span className="text-[15px] font-semibold text-[var(--color-accent)] tabular-nums">
-                    {entry.duration_seconds
-                      ? formatDuration(entry.duration_seconds)
+                    {entry.type === "breast"
+                      ? entry.duration_seconds
+                        ? formatDuration(entry.duration_seconds)
+                        : "-"
                       : entry.amount_ml
                         ? `${entry.amount_ml}ml`
                         : "-"}
diff --git a/worker/routes/feed.ts b/worker/routes/feed.ts
index af4a294..9c61ad7 100644
--- a/worker/routes/feed.ts
+++ b/worker/routes/feed.ts
@@ -158,19 +158,24 @@ feed.put("/:id", zValidator("json", editSchema), async (c) => {
   if (body.amount_ml !== undefined) updates.amount_ml = body.amount_ml;
   if (body.notes !== undefined) updates.notes = body.notes;
 
-  // Recalculate duration if times changed (breast feeds)
-  const startedAt = (updates.started_at as string) ?? entry.started_at;
-  const endedAt = (updates.ended_at as string) ?? entry.ended_at;
-  if (
-    (body.started_at !== undefined || body.ended_at !== undefined) &&
-    endedAt
-  ) {
-    const pauses: Pause[] = JSON.parse(entry.pauses);
-    updates.duration_seconds = calculateElapsedSeconds(
-      startedAt,
-      pauses,
-      endedAt,
-    );
+  if (entry.type === "breast") {
+    // Recalculate duration if times changed
+    const startedAt = (updates.started_at as string) ?? entry.started_at;
+    const endedAt = (updates.ended_at as string) ?? entry.ended_at;
+    if (
+      (body.started_at !== undefined || body.ended_at !== undefined) &&
+      endedAt
+    ) {
+      const pauses: Pause[] = JSON.parse(entry.pauses);
+      updates.duration_seconds = calculateElapsedSeconds(
+        startedAt,
+        pauses,
+        endedAt,
+      );
+    }
+  } else if (body.started_at !== undefined) {
+    // Formula/expressed are instant events — keep ended_at in sync
+    updates.ended_at = body.started_at;
   }
 
   await repo.update(id, updates);