diff --git a/src/quartermaster/routes.py b/src/quartermaster/routes.py
index eece90a..8642e5c 100644
--- a/src/quartermaster/routes.py
+++ b/src/quartermaster/routes.py
@@ -162,6 +162,34 @@ def edit_entry(
     return _render_section(request, db, entry.section, editing_id=entry.id)
 
 
+@router.post("/entries/{entry_id}", response_class=HTMLResponse)
+def save_entry(
+    entry_id: int,
+    request: Request,
+    name: str = Form(...),
+    amount: str = Form(...),
+    notes: str | None = Form(None),
+    db: Session = Depends(get_session),
+) -> HTMLResponse:
+    clean_name = name.strip()
+    if not clean_name:
+        raise HTTPException(status_code=400, detail="name is required")
+    parsed = _parse_amount(amount)
+    updated = service.update_entry(
+        db, entry_id, name=clean_name, amount=parsed, notes=notes
+    )
+    if updated is None:
+        raise HTTPException(status_code=404, detail="entry not found")
+    response = _render_section(request, db, updated.section)
+    extras: list[HTMLResponse] = [
+        _render_zero(request, db),
+        _render_group_totals(request, db),
+    ]
+    if updated.section == Section.debt_minimum:
+        extras.append(_render_target(request, db))
+    return _append_oob(response, *extras)
+
+
 @router.post("/entries/{entry_id}/notes", response_class=HTMLResponse)
 def update_entry_notes(
     entry_id: int,
diff --git a/tests/test_routes.py b/tests/test_routes.py
index 72767e8..ff301d2 100644
--- a/tests/test_routes.py
+++ b/tests/test_routes.py
@@ -114,3 +114,93 @@ def test_get_entry_edit_other_rows_stay_in_read_mode(client):
     assert response.status_code == 200
     assert response.text.count('entry-row editing') == 1
     assert response.text.count('entry-row reading') == 1
+
+
+def test_post_entry_updates_name_and_amount(client):
+    client.post(
+        "/sections/subscription/entries",
+        data={"name": "Twitch", "amount": "10.99"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "Twitch Prime", "amount": "11.99", "notes": ""},
+    )
+    assert response.status_code == 200
+    assert "Twitch Prime" in response.text
+    assert "$11.99" in response.text
+    # returns to read mode
+    assert 'class="entry-row reading"' in response.text
+    # OOB swaps for zero widget and group total
+    assert 'id="zero-widget"' in response.text
+    assert 'id="group-total-flexible"' in response.text
+
+
+def test_post_entry_updates_notes_as_badge(client):
+    client.post(
+        "/sections/subscription/entries",
+        data={"name": "Spotify", "amount": "17.48"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "Spotify", "amount": "17.48", "notes": "family plan"},
+    )
+    assert response.status_code == 200
+    assert "note-badge" in response.text
+    assert "family plan" in response.text
+
+
+def test_post_entry_debt_minimum_includes_target_oob(client):
+    client.post(
+        "/sections/debt_minimum/entries",
+        data={"name": "Card A", "amount": "50.00"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "Card A", "amount": "60.00", "notes": ""},
+    )
+    assert response.status_code == 200
+    assert 'id="section-debt_target"' in response.text
+
+
+def test_post_entry_empty_name_returns_400(client):
+    client.post(
+        "/sections/subscription/entries",
+        data={"name": "Twitch", "amount": "10.99"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "   ", "amount": "11.99", "notes": ""},
+    )
+    assert response.status_code == 400
+
+
+def test_post_entry_negative_amount_returns_400(client):
+    client.post(
+        "/sections/subscription/entries",
+        data={"name": "Twitch", "amount": "10.99"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "Twitch", "amount": "-1.00", "notes": ""},
+    )
+    assert response.status_code == 400
+
+
+def test_post_entry_non_numeric_amount_returns_400(client):
+    client.post(
+        "/sections/subscription/entries",
+        data={"name": "Twitch", "amount": "10.99"},
+    )
+    response = client.post(
+        "/entries/1",
+        data={"name": "Twitch", "amount": "eleven", "notes": ""},
+    )
+    assert response.status_code == 400
+
+
+def test_post_entry_missing_returns_404(client):
+    response = client.post(
+        "/entries/9999",
+        data={"name": "Whatever", "amount": "1.00", "notes": ""},
+    )
+    assert response.status_code == 404