diff --git a/src/components/collections/payment-plans-panel.tsx b/src/components/collections/payment-plans-panel.tsx
index cef9093..33bff81 100644
--- a/src/components/collections/payment-plans-panel.tsx
+++ b/src/components/collections/payment-plans-panel.tsx
@@ -65,7 +65,13 @@ function addInterval(dateStr: string, frequency: Frequency, n: number) {
   return d.toISOString().slice(0, 10);
 }
 
-export function PaymentPlansPanel({ collectionId }: { collectionId: string }) {
+export function PaymentPlansPanel({
+  collectionId,
+  caseId,
+}: {
+  collectionId: string;
+  caseId?: string | null;
+}) {
   const { user } = useAuth();
   const [plans, setPlans] = useState<Plan[]>([]);
   const [installments, setInstallments] = useState<Record<string, Installment[]>>({});
@@ -119,6 +125,25 @@ export function PaymentPlansPanel({ collectionId }: { collectionId: string }) {
     else load();
   };
 
+  const updatePaidAmount = async (id: string, value: string) => {
+    const num = value === "" ? null : parseFloat(value) || 0;
+    setInstallments((prev) => {
+      const next: Record<string, Installment[]> = {};
+      Object.entries(prev).forEach(([k, list]) => {
+        next[k] = list.map((x) => (x.id === id ? { ...x, paid_amount: num } : x));
+      });
+      return next;
+    });
+    const { error } = await supabase
+      .from("payment_plan_installments")
+      .update({ paid_amount: num })
+      .eq("id", id);
+    if (error) {
+      toast.error("Could not save", { description: error.message });
+      load();
+    }
+  };
+
   const updatePlanStatus = async (planId: string, status: PlanStatus) => {
     const { error } = await supabase
       .from("payment_plans")
@@ -220,8 +245,21 @@ export function PaymentPlansPanel({ collectionId }: { collectionId: string }) {
                                 {overdue && " · overdue"}
                               </div>
                             </div>
-                            <div className="text-sm font-medium tabular-nums">
-                              {formatCurrency(i.amount)}
+                            <div className="flex items-center gap-2">
+                              {i.paid ? (
+                                <Input
+                                  type="number"
+                                  step="0.01"
+                                  value={i.paid_amount ?? i.amount}
+                                  onChange={(e) => updatePaidAmount(i.id, e.target.value)}
+                                  className="h-7 w-[100px] text-sm text-right tabular-nums"
+                                  title="Amount paid"
+                                />
+                              ) : (
+                                <div className="text-sm font-medium tabular-nums">
+                                  {formatCurrency(i.amount)}
+                                </div>
+                              )}
                             </div>
                           </div>
                         );
@@ -243,6 +281,7 @@ export function PaymentPlansPanel({ collectionId }: { collectionId: string }) {
           open={createOpen}
           onOpenChange={setCreateOpen}
           collectionId={collectionId}
+          caseId={caseId ?? null}
           userId={user?.id}
           onSaved={load}
         />
@@ -264,12 +303,14 @@ function CreatePlanDialog({
   open,
   onOpenChange,
   collectionId,
+  caseId,
   userId,
   onSaved,
 }: {
   open: boolean;
   onOpenChange: (v: boolean) => void;
   collectionId: string;
+  caseId?: string | null;
   userId?: string;
   onSaved: () => void;
 }) {
@@ -307,6 +348,7 @@ function CreatePlanDialog({
       .from("payment_plans")
       .insert({
         collection_id: collectionId,
+        case_id: caseId ?? null,
         name: name || null,
         total_amount: t,
         down_payment: parseFloat(down) || 0,
diff --git a/src/routes/collections.$collectionId.tsx b/src/routes/collections.$collectionId.tsx
index 5d0fcc4..351d5cb 100644
--- a/src/routes/collections.$collectionId.tsx
+++ b/src/routes/collections.$collectionId.tsx
@@ -598,7 +598,7 @@ function CollectionDetailRoute() {
             </Card>
 
             {/* Payment plans */}
-            <PaymentPlansPanel collectionId={collection.id} />
+            <PaymentPlansPanel collectionId={collection.id} caseId={collection.case_id ?? null} />
 
             {/* Ledger */}
             <CollectionDetail
diff --git a/supabase/migrations/20260426085228_8b01c824-d7a9-43e8-aedb-3c0a89d3c06d.sql b/supabase/migrations/20260426085228_8b01c824-d7a9-43e8-aedb-3c0a89d3c06d.sql
new file mode 100644
index 0000000..3adcabf
--- /dev/null
+++ b/supabase/migrations/20260426085228_8b01c824-d7a9-43e8-aedb-3c0a89d3c06d.sql
@@ -0,0 +1,29 @@
+-- Backfill case_id on payment_plans created via collections so they show up
+-- on the case Payment Plans tab.
+UPDATE public.payment_plans pp
+SET case_id = c.case_id
+FROM public.collections c
+WHERE pp.collection_id = c.id
+  AND pp.case_id IS NULL
+  AND c.case_id IS NOT NULL;
+
+-- Trigger to auto-populate case_id on insert/update when collection_id is set
+-- but case_id is missing.
+CREATE OR REPLACE FUNCTION public.payment_plans_fill_case_id()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+BEGIN
+  IF NEW.case_id IS NULL AND NEW.collection_id IS NOT NULL THEN
+    SELECT case_id INTO NEW.case_id FROM public.collections WHERE id = NEW.collection_id;
+  END IF;
+  RETURN NEW;
+END;
+$$;
+
+DROP TRIGGER IF EXISTS payment_plans_fill_case_id_trg ON public.payment_plans;
+CREATE TRIGGER payment_plans_fill_case_id_trg
+BEFORE INSERT OR UPDATE ON public.payment_plans
+FOR EACH ROW EXECUTE FUNCTION public.payment_plans_fill_case_id();
\ No newline at end of file