diff --git a/src/main/java/com/sampoom/backend/api/bom/controller/BomController.java b/src/main/java/com/sampoom/backend/api/bom/controller/BomController.java
index 0eb1523..2070d44 100644
--- a/src/main/java/com/sampoom/backend/api/bom/controller/BomController.java
+++ b/src/main/java/com/sampoom/backend/api/bom/controller/BomController.java
@@ -77,4 +77,18 @@ public ResponseEntity<ApiResponse<PageResponseDTO<BomResponseDTO>>> searchBoms(
         return ApiResponse.success(SuccessStatus.OK,
                 bomService.searchBoms(keyword, categoryId, groupId, status, complexity, page, size));
     }
+//
+//    @Operation(summary = "모든 BOM totalCost 재계산", description = "quantity가 Double로 변경된 후 모든 BOM의 totalCost를 재계산합니다.")
+//    @PostMapping("/recalculate-all-costs")
+//    public ResponseEntity<ApiResponse<Void>> recalculateAllBomTotalCosts() {
+//        bomService.recalculateAllBomTotalCosts();
+//        return ApiResponse.success_only(SuccessStatus.OK);
+//    }
+//
+//    @Operation(summary = "특정 BOM totalCost 재계산", description = "특정 BOM의 totalCost를 재계산합니다.")
+//    @PostMapping("/{bomId}/recalculate-cost")
+//    public ResponseEntity<ApiResponse<Void>> recalculateBomTotalCost(@PathVariable Long bomId) {
+//        bomService.recalculateBomTotalCost(bomId);
+//        return ApiResponse.success_only(SuccessStatus.OK);
+//    }
 }
diff --git a/src/main/java/com/sampoom/backend/api/bom/dto/BomDetailResponseDTO.java b/src/main/java/com/sampoom/backend/api/bom/dto/BomDetailResponseDTO.java
index ab24054..8f45f47 100644
--- a/src/main/java/com/sampoom/backend/api/bom/dto/BomDetailResponseDTO.java
+++ b/src/main/java/com/sampoom/backend/api/bom/dto/BomDetailResponseDTO.java
@@ -32,12 +32,11 @@ public class BomDetailResponseDTO {
     @AllArgsConstructor
     @Builder
     public static class BomMaterialDTO {
-        private Long id;
         private Long materialId;
         private String materialName;
         private String materialCode;
         private String unit;
-        private Long quantity;
+        private Double quantity;
         private Long standardCost;  // 단가
         private Long total;  // 단가 * 수량
     }
@@ -46,10 +45,9 @@ public static BomDetailResponseDTO from(Bom bom) {
         List<BomMaterialDTO> materialDtos = bom.getMaterials().stream()
                 .map(material -> {
                     Long cost = Optional.ofNullable(material.getMaterial().getStandardCost()).orElse(0L);
-                    Long total = cost * Optional.ofNullable(material.getQuantity()).orElse(0L);
+                    Long total = cost * Optional.ofNullable(material.getQuantity()).orElse(0.0).longValue();
 
                     return BomMaterialDTO.builder()
-                            .id(material.getId())
                             .materialId(material.getMaterial().getId())
                             .materialName(material.getMaterial().getName())
                             .materialCode(material.getMaterial().getMaterialCode())
diff --git a/src/main/java/com/sampoom/backend/api/bom/dto/BomRequestDTO.java b/src/main/java/com/sampoom/backend/api/bom/dto/BomRequestDTO.java
index 1e46151..12c7a5e 100644
--- a/src/main/java/com/sampoom/backend/api/bom/dto/BomRequestDTO.java
+++ b/src/main/java/com/sampoom/backend/api/bom/dto/BomRequestDTO.java
@@ -23,6 +23,6 @@ public class BomRequestDTO {
     @Builder
     public static class BomMaterialDTO {
         private Long materialId;
-        private Long quantity;
+        private Double quantity;
     }
 }
diff --git a/src/main/java/com/sampoom/backend/api/bom/dto/BomResponseDTO.java b/src/main/java/com/sampoom/backend/api/bom/dto/BomResponseDTO.java
index d9d463e..f98e2ad 100644
--- a/src/main/java/com/sampoom/backend/api/bom/dto/BomResponseDTO.java
+++ b/src/main/java/com/sampoom/backend/api/bom/dto/BomResponseDTO.java
@@ -57,8 +57,8 @@ public static BomResponseDTO from(Bom bom) {
 
         // 실시간 계산
         int componentCount = materials.size();
-        long totalQuantity = materials.stream()
-                .mapToLong(BomMaterialResponse::getQuantity)
+        long totalQuantity = (long) materials.stream()
+                .mapToDouble(BomMaterialResponse::getQuantity)
                 .sum();
 
         return BomResponseDTO.builder()
@@ -93,16 +93,13 @@ public static class BomMaterialResponse {
         private String materialName;
         private String materialCode;
         private String unit;
-        private Long quantity;
+        private Double quantity;
         private Long standardCost;
         private Long total;  // 단가 * 수량
 
         public static BomMaterialResponse from(BomMaterial bm) {
             Long cost = bm.getMaterial().getStandardCost() != null
-                    ? bm.getMaterial().getStandardCost()
-                    : 0L;
-            Long total = cost * bm.getQuantity();
-
+                    ? bm.getMaterial().getStandardCost() : 0L;
             return BomMaterialResponse.builder()
                     .materialId(bm.getMaterial().getId())
                     .materialName(bm.getMaterial().getName())
@@ -110,7 +107,7 @@ public static BomMaterialResponse from(BomMaterial bm) {
                     .unit(bm.getMaterial().getMaterialUnit())
                     .quantity(bm.getQuantity())
                     .standardCost(cost)
-                    .total(total)
+                    .total(cost * bm.getQuantity().longValue()) // Double을 Long으로 변환
                     .build();
         }
     }
diff --git a/src/main/java/com/sampoom/backend/api/bom/entity/Bom.java b/src/main/java/com/sampoom/backend/api/bom/entity/Bom.java
index 214726a..a0d239a 100644
--- a/src/main/java/com/sampoom/backend/api/bom/entity/Bom.java
+++ b/src/main/java/com/sampoom/backend/api/bom/entity/Bom.java
@@ -70,8 +70,8 @@ public void addMaterial(BomMaterial bomMaterial) {
     public void calculateTotalCost() {
         this.totalCost = this.materials.stream()
                 .mapToLong(m -> {
-                    if (m.getMaterial().getStandardCost() == null) return 0L;
-                    return m.getMaterial().getStandardCost() * m.getQuantity();
+                    if (m.getMaterial().getStandardCost() == null || m.getQuantity() == null) return 0L;
+                    return (long) (m.getMaterial().getStandardCost() * m.getQuantity());
                 })
                 .sum();
     }
diff --git a/src/main/java/com/sampoom/backend/api/bom/entity/BomMaterial.java b/src/main/java/com/sampoom/backend/api/bom/entity/BomMaterial.java
index fdba030..7ce5ba4 100644
--- a/src/main/java/com/sampoom/backend/api/bom/entity/BomMaterial.java
+++ b/src/main/java/com/sampoom/backend/api/bom/entity/BomMaterial.java
@@ -27,13 +27,13 @@ public class BomMaterial {
     @JoinColumn(name = "material_id", nullable = false)
     private Material material;
 
-    private Long quantity;
+    private Double quantity;
 
     public void updateBom(Bom bom) {
         this.bom = bom;
     }
 
-    public void updateQuantity(Long quantity) {
+    public void updateQuantity(Double quantity) {
         this.quantity = quantity;
     }
 
diff --git a/src/main/java/com/sampoom/backend/api/bom/event/dto/BomEvent.java b/src/main/java/com/sampoom/backend/api/bom/event/dto/BomEvent.java
index 631336e..164df6c 100644
--- a/src/main/java/com/sampoom/backend/api/bom/event/dto/BomEvent.java
+++ b/src/main/java/com/sampoom/backend/api/bom/event/dto/BomEvent.java
@@ -45,7 +45,7 @@ public static class MaterialInfo {
             private String materialName;
             private String materialCode;
             private String unit;
-            private Long quantity;
+            private Double quantity;
         }
     }
 }
diff --git a/src/main/java/com/sampoom/backend/api/bom/service/BomService.java b/src/main/java/com/sampoom/backend/api/bom/service/BomService.java
index 6fcfd82..75de864 100644
--- a/src/main/java/com/sampoom/backend/api/bom/service/BomService.java
+++ b/src/main/java/com/sampoom/backend/api/bom/service/BomService.java
@@ -55,11 +55,11 @@ public BomResponseDTO createBom(BomRequestDTO requestDTO) {
         }
 
         // 요청 자재 중복 제거 및 수량 합산
-        Map<Long, Long> idToQty = requestDTO.getMaterials().stream()
+        Map<Long, Double> idToQty = requestDTO.getMaterials().stream()
                 .collect(Collectors.toMap(
                         BomRequestDTO.BomMaterialDTO::getMaterialId,
                         BomRequestDTO.BomMaterialDTO::getQuantity,
-                        Long::sum // 중복 materialId 수량 합산
+                        Double::sum // 중복 materialId 수량 합산
                 ));
 
         // 한 번의 쿼리로 모든 자재 조회 (N+1 방지)
@@ -105,7 +105,7 @@ public BomResponseDTO createBom(BomRequestDTO requestDTO) {
 
         // 5️⃣ 자재 매핑
         for (Material material : materials) {
-            Long quantity = idToQty.get(material.getId());
+            Double quantity = idToQty.get(material.getId());
             BomMaterial bm = BomMaterial.builder()
                     .bom(bom)
                     .material(material)
@@ -347,4 +347,27 @@ public void updateBomStatus(Long bomId, BomStatus newStatus) {
         bom.updateStatus(newStatus);
         bomRepository.save(bom);
     }
+
+    /**
+     * 모든 BOM의 totalCost 재계산 (quantity가 Double로 변경된 후 실행)
+     */
+    @Transactional
+    public void recalculateAllBomTotalCosts() {
+        List<Bom> boms = bomRepository.findAll();
+        for (Bom bom : boms) {
+            bom.calculateTotalCost();
+        }
+        bomRepository.saveAll(boms);
+    }
+
+    /**
+     * 특정 BOM의 totalCost 재계산
+     */
+    @Transactional
+    public void recalculateBomTotalCost(Long bomId) {
+        Bom bom = bomRepository.findById(bomId)
+                .orElseThrow(() -> new NotFoundException(ErrorStatus.BOM_NOT_FOUND));
+        bom.calculateTotalCost();
+        bomRepository.save(bom);
+    }
 }
diff --git a/src/main/java/com/sampoom/backend/api/part/controller/PartController.java b/src/main/java/com/sampoom/backend/api/part/controller/PartController.java
index 08b3984..0396d54 100644
--- a/src/main/java/com/sampoom/backend/api/part/controller/PartController.java
+++ b/src/main/java/com/sampoom/backend/api/part/controller/PartController.java
@@ -107,4 +107,18 @@ public ResponseEntity<ApiResponse<PartListResponseDTO>> updatePart(
 //
 //        return ApiResponse.success(SuccessStatus.PART_LIST_SUCCESS, partPage);
 //    }
+//
+//    @Operation(summary = "모든 Part standard_total_cost 재계산", description = "standard_total_cost 컬럼 추가 후 모든 Part의 비용을 재계산합니다.")
+//    @PostMapping("/recalculate-all-costs")
+//    public ResponseEntity<ApiResponse<Void>> recalculateAllPartStandardCosts() {
+//        partService.recalculateAllPartStandardCosts();
+//        return ApiResponse.success_only(SuccessStatus.OK);
+//    }
+//
+//    @Operation(summary = "특정 Part standard_total_cost 재계산", description = "특정 Part의 standard_total_cost를 재계산합니다.")
+//    @PostMapping("/{partId}/recalculate-cost")
+//    public ResponseEntity<ApiResponse<Void>> recalculatePartStandardCost(@PathVariable Long partId) {
+//        partService.recalculatePartStandardCost(partId);
+//        return ApiResponse.success_only(SuccessStatus.OK);
+//    }
 }
diff --git a/src/main/java/com/sampoom/backend/api/part/entity/Part.java b/src/main/java/com/sampoom/backend/api/part/entity/Part.java
index f788fc3..cc612ab 100644
--- a/src/main/java/com/sampoom/backend/api/part/entity/Part.java
+++ b/src/main/java/com/sampoom/backend/api/part/entity/Part.java
@@ -36,6 +36,8 @@ public class Part extends BaseTimeEntity {
 
     private Long standardCost; // 표준 단가 (자동 계산, 입력 X)
 
+    @Column(name = "standard_total_cost")
+    private Long standardTotalCost; // 표준 총비용 (BOM 비용 * 기준수량 + 공정비)
 
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "group_id", nullable = false)
@@ -99,11 +101,67 @@ public void changeCode(String newCode) {
 
     // Part의 총 비용을 BOM 비용과 Process 비용을 합쳐서 계산하는 메서드
     public void calculateStandardCost(Long bomCost, Long processCost) {
-        this.standardCost = (bomCost != null ? bomCost : 0L) + (processCost != null ? processCost : 0L);
+        // standard_total_cost = bom 비용 * standard_quantity + 공정비
+        Long bomTotalCost = (bomCost != null ? bomCost : 0L) * (standardQuantity != null ? standardQuantity : 1);
+        Long totalProcessCost = processCost != null ? processCost : 0L;
+        this.standardTotalCost = bomTotalCost + totalProcessCost;
+
+        // standard_cost = standard_total_cost / standard_quantity (1000원 단위로 반올림)
+        Long rawStandardCost = this.standardQuantity != null && this.standardQuantity > 0
+            ? this.standardTotalCost / this.standardQuantity
+            : this.standardTotalCost;
+        this.standardCost = roundToThousand(rawStandardCost);
+    }
+
+    // BOM 비용과 공정비를 분리해서 계산하는 새로운 메서드
+    public void calculateStandardCostAndTotal(Long bomCost, Long processCost) {
+        Long bomUnitCost = bomCost != null ? bomCost : 0L;
+        Long processUnitCost = processCost != null ? processCost : 0L;
+        Integer qty = standardQuantity != null ? standardQuantity : 1;
+
+        // standard_total_cost = bom 비용 * standard_quantity + 공정비
+        this.standardTotalCost = (bomUnitCost * qty) + processUnitCost;
+
+        // standard_cost = standard_total_cost / standard_quantity (1000원 단위로 반올림)
+        Long rawStandardCost = qty > 0 ? this.standardTotalCost / qty : this.standardTotalCost;
+        this.standardCost = roundToThousand(rawStandardCost);
     }
 
     // standardCost 직접 설정 메서드 (필요시)
     public void setStandardCost(Long standardCost) {
-        this.standardCost = standardCost;
+        this.standardCost = roundToThousand(standardCost);
+    }
+
+    // standardTotalCost 직접 설정 메서드
+    public void setStandardTotalCost(Long standardTotalCost) {
+        this.standardTotalCost = standardTotalCost;
+        // standard_cost 재계산 (1000원 단위로 반올림)
+        Long rawStandardCost = this.standardQuantity != null && this.standardQuantity > 0
+            ? this.standardTotalCost / this.standardQuantity
+            : this.standardTotalCost;
+        this.standardCost = roundToThousand(rawStandardCost);
+    }
+
+    // standardQuantity 변경 시 비용 재계산
+    public void updateStandardQuantity(Integer standardQuantity) {
+        this.standardQuantity = standardQuantity;
+        // 기존 standardTotalCost가 있다면 standardCost 재계산 (1000원 단위로 반올림)
+        if (this.standardTotalCost != null) {
+            Long rawStandardCost = standardQuantity != null && standardQuantity > 0
+                ? this.standardTotalCost / standardQuantity
+                : this.standardTotalCost;
+            this.standardCost = roundToThousand(rawStandardCost);
+        }
+    }
+
+    /**
+     * 1000원 단위로 반올림하는 헬퍼 메서드
+     */
+    private Long roundToThousand(Long amount) {
+        if (amount == null) {
+            return null;
+        }
+        // 1000으로 나누고 반올림한 후 다시 1000을 곱함
+        return Math.round(amount / 1000.0) * 1000L;
     }
 }
diff --git a/src/main/java/com/sampoom/backend/api/part/event/dto/PartEvent.java b/src/main/java/com/sampoom/backend/api/part/event/dto/PartEvent.java
index 0d648fc..f642b8b 100644
--- a/src/main/java/com/sampoom/backend/api/part/event/dto/PartEvent.java
+++ b/src/main/java/com/sampoom/backend/api/part/event/dto/PartEvent.java
@@ -35,5 +35,6 @@ public static class Payload {
         private Long categoryId;
 
         private Long standardCost;
+        private Long standardTotalCost; // 표준 총비용 추가
     }
 }
diff --git a/src/main/java/com/sampoom/backend/api/part/event/service/PartEventBatchService.java b/src/main/java/com/sampoom/backend/api/part/event/service/PartEventBatchService.java
index e3671cb..9970511 100644
--- a/src/main/java/com/sampoom/backend/api/part/event/service/PartEventBatchService.java
+++ b/src/main/java/com/sampoom/backend/api/part/event/service/PartEventBatchService.java
@@ -61,6 +61,7 @@ public void publishAllPartEvents() {
                                 .groupId(group != null ? group.getId() : null)
                                 .categoryId(category != null ? category.getId() : null)
                                 .standardCost(part.getStandardCost())
+                                .standardTotalCost(part.getStandardTotalCost())
                                 .build())
                         .build();
 
diff --git a/src/main/java/com/sampoom/backend/api/part/service/PartService.java b/src/main/java/com/sampoom/backend/api/part/service/PartService.java
index 1e07c00..75c0d97 100644
--- a/src/main/java/com/sampoom/backend/api/part/service/PartService.java
+++ b/src/main/java/com/sampoom/backend/api/part/service/PartService.java
@@ -170,6 +170,7 @@ public PartListResponseDTO createPart(PartCreateRequestDTO partCreateRequestDTO)
                         .groupId(partGroup.getId())
                         .categoryId(partGroup.getCategory().getId())
                         .standardCost(savedPart.getStandardCost())
+                        .standardTotalCost(savedPart.getStandardTotalCost())
                         .build())
                 .build();
 
@@ -231,6 +232,7 @@ public PartListResponseDTO updatePart(Long partId, PartUpdateRequestDTO partUpda
                             .groupId(part.getPartGroup().getId())
                             .categoryId(part.getPartGroup().getCategory().getId())
                             .standardCost(part.getStandardCost())
+                            .standardTotalCost(part.getStandardTotalCost())
                             .build())
                     .build();
 
@@ -283,6 +285,7 @@ public void deletePart(Long partId) {
                         .groupId(part.getPartGroup().getId())
                         .categoryId(part.getPartGroup().getCategory().getId())
                         .standardCost(part.getStandardCost())
+                        .standardTotalCost(part.getStandardTotalCost())
                         .build())
                 .build();
 
@@ -430,6 +433,7 @@ public void publishPartUpdatedEvent(Part part) {
                         .groupId(part.getPartGroup().getId())
                         .categoryId(part.getPartGroup().getCategory().getId())
                         .standardCost(part.getStandardCost())
+                        .standardTotalCost(part.getStandardTotalCost())
                         .build())
                 .build();
 
@@ -481,4 +485,33 @@ public Long getProcessCostByPartId(Long partId) {
         Process process = processRepository.findByPartId(partId).orElse(null);
         return process != null ? process.getTotalProcessCost() : 0L;
     }
+
+    /**
+     * 모든 Part의 standard_total_cost 재계산
+     */
+    @Transactional
+    public void recalculateAllPartStandardCosts() {
+        List<Part> parts = partRepository.findAll();
+        for (Part part : parts) {
+            Long bomCost = getBomCostByPartId(part.getId());
+            Long processCost = getProcessCostByPartId(part.getId());
+            part.calculateStandardCost(bomCost, processCost);
+        }
+        partRepository.saveAll(parts);
+    }
+
+    /**
+     * 특정 Part의 standard_total_cost 재계산
+     */
+    @Transactional
+    public void recalculatePartStandardCost(Long partId) {
+        Part part = partRepository.findById(partId)
+                .orElseThrow(() -> new NotFoundException(ErrorStatus.PART_NOT_FOUND));
+
+        Long bomCost = getBomCostByPartId(partId);
+        Long processCost = getProcessCostByPartId(partId);
+        part.calculateStandardCost(bomCost, processCost);
+
+        partRepository.save(part);
+    }
 }