diff --git a/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx b/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
index 4214935..69dfdf3 100644
--- a/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
+++ b/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
@@ -369,12 +369,12 @@ export default function FertilizerEditPage({ planId }: { planId?: number }) {
   const getPlanAvailableStock = (fertilizer: Fertilizer) => {
     const stock = getStockInfo(fertilizer);
     if (!stock) return null;
-    return getNumericValue(stock.available_stock) + (initialPlanTotals[fertilizer.id] ?? 0);
+    return getNumericValue(stock.available_stock);
   };
   const getPlanShortage = (fertilizer: Fertilizer) => {
     const available = getPlanAvailableStock(fertilizer);
     if (available === null) return 0;
-    return Math.max(colTotal(fertilizer.id) - available, 0);
+    return available < 0 ? Math.abs(available) : 0;
   };
 
   // ─── 保存（adjusted 優先、なければ calc 値を使用）