diff --git a/src/components/production/WorkerScreen/MaterialInputModal.tsx b/src/components/production/WorkerScreen/MaterialInputModal.tsx
index 64d3ce49..2b1d4131 100644
--- a/src/components/production/WorkerScreen/MaterialInputModal.tsx
+++ b/src/components/production/WorkerScreen/MaterialInputModal.tsx
@@ -199,10 +199,9 @@ export function MaterialInputModal({
     return group.alreadyInputted > 0 ? group.requiredQty : group.effectiveRequiredQty;
   }, []);
 
-  // 배정 수량 계산 (manual 우선 → 나머지 FIFO 자동배분, 물리LOT 교차그룹 추적)
+  // 배정 수량 계산 (manual 우선 → 나머지 FIFO 자동배분, 그룹별 독립)
   const allocations = useMemo(() => {
     const result = new Map<string, number>();
-    const physicalUsed = new Map<number, number>(); // stockLotId → 그룹 간 누적 사용량
 
     for (const group of materialGroups) {
       const targetQty = getGroupTargetQty(group);
@@ -215,24 +214,18 @@ export function MaterialInputModal({
           const val = manualAllocations.get(lotKey)!;
           result.set(lotKey, val);
           remaining -= val;
-          physicalUsed.set(lot.stockLotId, (physicalUsed.get(lot.stockLotId) || 0) + val);
         }
       }
 
-      // 2차: non-manual 선택 로트 FIFO 자동배분 (물리LOT 가용량 고려)
+      // 2차: non-manual 선택 로트 FIFO 자동배분 (그룹 내 독립 계산)
       for (const lot of group.lots) {
         const lotKey = getLotKey(lot, group.groupKey);
         if (selectedLotKeys.has(lotKey) && lot.stockLotId && !manualAllocations.has(lotKey)) {
           const itemInput = lot as unknown as MaterialForItemInput;
           const maxAvail = lot.lotAvailableQty + (itemInput.lotInputtedQty ?? 0);
-          const used = physicalUsed.get(lot.stockLotId) || 0;
-          const effectiveAvail = Math.max(0, maxAvail - used);
-          const alloc = remaining > 0 ? Math.min(effectiveAvail, remaining) : 0;
+          const alloc = remaining > 0 ? Math.min(maxAvail, remaining) : 0;
           result.set(lotKey, alloc);
           remaining -= alloc;
-          if (alloc > 0) {
-            physicalUsed.set(lot.stockLotId, used + alloc);
-          }
         }
       }
     }
@@ -286,11 +279,10 @@ export function MaterialInputModal({
     });
   }, []);
 
-  // FIFO 자동입력 (물리LOT 교차그룹 가용량 추적)
+  // FIFO 자동입력 (그룹별 독립 배정 — 각 그룹의 LOT 가용량 독립 계산)
   const handleAutoFill = useCallback(() => {
     const newSelected = new Set<string>();
     const newAllocations = new Map<string, number>();
-    const physicalUsed = new Map<number, number>(); // stockLotId → 그룹 간 누적 사용량
 
     for (const group of materialGroups) {
       const targetQty = getGroupTargetQty(group);
@@ -301,15 +293,13 @@ export function MaterialInputModal({
         if (!lot.stockLotId || remaining <= 0) continue;
         const lotKey = getLotKey(lot, group.groupKey);
         const itemInput = lot as unknown as MaterialForItemInput;
+        // 해당 그룹에서의 LOT 가용량 = 현재 가용 + 이 그룹에서 기투입된 수량
         const maxAvail = lot.lotAvailableQty + (itemInput.lotInputtedQty ?? 0);
-        const used = physicalUsed.get(lot.stockLotId) || 0;
-        const effectiveAvail = Math.max(0, maxAvail - used);
-        const alloc = Math.min(effectiveAvail, remaining);
+        const alloc = Math.min(maxAvail, remaining);
         if (alloc > 0) {
           newSelected.add(lotKey);
           newAllocations.set(lotKey, alloc);
           remaining -= alloc;
-          physicalUsed.set(lot.stockLotId, used + alloc);
         }
       }
     }