diff --git a/src/components/production/WorkerScreen/MaterialInputModal.tsx b/src/components/production/WorkerScreen/MaterialInputModal.tsx
index f5e85204..449ef9b0 100644
--- a/src/components/production/WorkerScreen/MaterialInputModal.tsx
+++ b/src/components/production/WorkerScreen/MaterialInputModal.tsx
@@ -203,15 +203,20 @@ export function MaterialInputModal({
   const allocations = useMemo(() => {
     const result = new Map<string, number>();
 
-    // 물리 LOT별 최대 가용량 초기화
+    // 물리 LOT별 실제 가용량: lotAvailableQty + SUM(모든 그룹의 lotInputtedQty)
     const physicalAvail = new Map<number, number>();
+    const lotBaseAvail = new Map<number, number>();
     for (const group of materialGroups) {
       for (const lot of group.lots) {
         if (!lot.stockLotId) continue;
         const itemInput = lot as unknown as MaterialForItemInput;
-        const totalAvail = lot.lotAvailableQty + (itemInput.lotInputtedQty ?? 0);
-        const current = physicalAvail.get(lot.stockLotId) ?? 0;
-        if (totalAvail > current) physicalAvail.set(lot.stockLotId, totalAvail);
+        const inputted = itemInput.lotInputtedQty ?? 0;
+        if (!lotBaseAvail.has(lot.stockLotId)) {
+          lotBaseAvail.set(lot.stockLotId, lot.lotAvailableQty);
+          physicalAvail.set(lot.stockLotId, lot.lotAvailableQty + inputted);
+        } else {
+          physicalAvail.set(lot.stockLotId, (physicalAvail.get(lot.stockLotId) ?? 0) + inputted);
+        }
       }
     }
     const physicalUsed = new Map<number, number>();
@@ -301,19 +306,22 @@ export function MaterialInputModal({
   const handleAutoFill = useCallback(() => {
     const newSelected = new Set<string>();
     const newAllocations = new Map<string, number>();
-    // 물리 LOT별 실제 가용량 추적 (lotAvailableQty 기준, 기투입분 포함 복원량으로 초기화)
-    const physicalAvail = new Map<number, number>();
 
-    // 1차: 물리 LOT별 최대 가용량 초기화 (lotAvailableQty + 전체 기투입량)
+    // 물리 LOT별 실제 가용량 계산: lotAvailableQty + SUM(모든 그룹의 lotInputtedQty)
+    // replace 모드에서 기투입분이 복원되므로 모든 그룹의 기투입을 합산
+    const physicalAvail = new Map<number, number>();
+    const lotBaseAvail = new Map<number, number>();
+
     for (const group of materialGroups) {
       for (const lot of group.lots) {
         if (!lot.stockLotId) continue;
         const itemInput = lot as unknown as MaterialForItemInput;
-        const totalAvail = lot.lotAvailableQty + (itemInput.lotInputtedQty ?? 0);
-        // 같은 stockLotId의 최대값 유지 (기투입이 가장 큰 값이 실제 원래 가용량)
-        const current = physicalAvail.get(lot.stockLotId) ?? 0;
-        if (totalAvail > current) {
-          physicalAvail.set(lot.stockLotId, totalAvail);
+        const inputted = itemInput.lotInputtedQty ?? 0;
+        if (!lotBaseAvail.has(lot.stockLotId)) {
+          lotBaseAvail.set(lot.stockLotId, lot.lotAvailableQty);
+          physicalAvail.set(lot.stockLotId, lot.lotAvailableQty + inputted);
+        } else {
+          physicalAvail.set(lot.stockLotId, (physicalAvail.get(lot.stockLotId) ?? 0) + inputted);
         }
       }
     }