diff --git a/cmd/reflow-quantity-product-warehouse-from-stock-allocation/main.go b/cmd/reflow-quantity-product-warehouse-from-stock-allocation/main.go
new file mode 100644
index 00000000..a4259bf1
--- /dev/null
+++ b/cmd/reflow-quantity-product-warehouse-from-stock-allocation/main.go
@@ -0,0 +1,282 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"strings"
+
+	"gitlab.com/mbugroup/lti-api.git/internal/config"
+	"gitlab.com/mbugroup/lti-api.git/internal/database"
+	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
+	"gitlab.com/mbugroup/lti-api.git/internal/utils/fifo"
+	"gorm.io/gorm"
+)
+
+const qtyEpsilon = 1e-6
+
+const (
+	levelAll                = 1
+	levelByProductName      = 2
+	levelByProductWarehouse = 3
+)
+
+type reflowRow struct {
+	ProductWarehouseID uint    `gorm:"column:product_warehouse_id"`
+	ProductID          uint    `gorm:"column:product_id"`
+	ProductName        string  `gorm:"column:product_name"`
+	CurrentQty         float64 `gorm:"column:current_qty"`
+	SumTotalQty        float64 `gorm:"column:sum_total_qty"`
+	SumAllocatedQty    float64 `gorm:"column:sum_allocated_qty"`
+	ComputedQty        float64 `gorm:"column:computed_qty"`
+}
+
+func main() {
+	var (
+		apply              bool
+		level              int
+		productName        string
+		productWarehouseID uint
+	)
+
+	flag.BoolVar(&apply, "apply", false, "Apply changes. If false, run as dry-run")
+	flag.IntVar(&level, "level", levelAll, "CLI level: 1=all product_warehouse scope, 2=product name scope, 3=product_warehouse_id scope")
+	flag.StringVar(&productName, "product-name", "", "Product name (required for level 2)")
+	flag.UintVar(&productWarehouseID, "product-warehouse-id", 0, "Product warehouse id (required for level 3)")
+	flag.Parse()
+
+	productName = strings.TrimSpace(productName)
+	if err := validateFlags(level, productName, productWarehouseID); err != nil {
+		log.Fatalf("invalid flags: %v", err)
+	}
+
+	ctx := context.Background()
+	db := database.Connect(config.DBHost, config.DBName)
+
+	rows, err := loadReflowRows(ctx, db, level, productName, productWarehouseID)
+	if err != nil {
+		log.Fatalf("failed to calculate reflow qty: %v", err)
+	}
+
+	fmt.Printf("Mode: %s\n", modeLabel(apply))
+	fmt.Printf("Level: %d (%s)\n", level, levelLabel(level))
+	if productName != "" {
+		fmt.Printf("Filter product_name: %s\n", productName)
+	}
+	if productWarehouseID > 0 {
+		fmt.Printf("Filter product_warehouse_id: %d\n", productWarehouseID)
+	}
+	fmt.Printf("Targets found: %d\n\n", len(rows))
+
+	if len(rows) == 0 {
+		fmt.Println("No product warehouse found from purchase_items scope")
+		return
+	}
+
+	negativePlan := 0
+	for _, row := range rows {
+		if row.ComputedQty < 0 {
+			negativePlan++
+		}
+
+		fmt.Printf(
+			"PLAN pw=%d product_id=%d product=%q current_qty=%.3f total_qty=%.3f allocated_qty=%.3f computed_qty=%.3f delta=%.3f\n",
+			row.ProductWarehouseID,
+			row.ProductID,
+			row.ProductName,
+			row.CurrentQty,
+			row.SumTotalQty,
+			row.SumAllocatedQty,
+			row.ComputedQty,
+			row.ComputedQty-row.CurrentQty,
+		)
+	}
+
+	if !apply {
+		fmt.Println()
+		fmt.Printf("Summary: planned=%d updated=0 skipped=0 failed=0 negative_plan=%d\n", len(rows), negativePlan)
+		return
+	}
+
+	updated := 0
+	skipped := 0
+	negativeUpdated := 0
+
+	err = db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		for _, row := range rows {
+			if nearlyEqual(row.CurrentQty, row.ComputedQty) {
+				fmt.Printf(
+					"SKIP pw=%d reason=no_change current_qty=%.3f computed_qty=%.3f\n",
+					row.ProductWarehouseID,
+					row.CurrentQty,
+					row.ComputedQty,
+				)
+				skipped++
+				continue
+			}
+
+			if err := tx.Table("product_warehouses").
+				Where("id = ?", row.ProductWarehouseID).
+				Update("qty", row.ComputedQty).Error; err != nil {
+				return fmt.Errorf("update qty for product_warehouse_id=%d: %w", row.ProductWarehouseID, err)
+			}
+
+			if row.ComputedQty < 0 {
+				negativeUpdated++
+			}
+
+			fmt.Printf(
+				"DONE pw=%d product_id=%d product=%q old_qty=%.3f new_qty=%.3f\n",
+				row.ProductWarehouseID,
+				row.ProductID,
+				row.ProductName,
+				row.CurrentQty,
+				row.ComputedQty,
+			)
+			updated++
+		}
+
+		return nil
+	})
+	if err != nil {
+		fmt.Println()
+		fmt.Printf(
+			"Summary: planned=%d updated=%d skipped=%d failed=1 negative_plan=%d negative_updated=%d\n",
+			len(rows),
+			updated,
+			skipped,
+			negativePlan,
+			negativeUpdated,
+		)
+		log.Printf("error: %v", err)
+		os.Exit(1)
+	}
+
+	fmt.Println()
+	fmt.Printf(
+		"Summary: planned=%d updated=%d skipped=%d failed=0 negative_plan=%d negative_updated=%d\n",
+		len(rows),
+		updated,
+		skipped,
+		negativePlan,
+		negativeUpdated,
+	)
+}
+
+func validateFlags(level int, productName string, productWarehouseID uint) error {
+	switch level {
+	case levelAll:
+		if productName != "" {
+			return errors.New("--product-name cannot be used on level 1")
+		}
+		if productWarehouseID > 0 {
+			return errors.New("--product-warehouse-id cannot be used on level 1")
+		}
+	case levelByProductName:
+		if productName == "" {
+			return errors.New("--product-name is required on level 2")
+		}
+		if productWarehouseID > 0 {
+			return errors.New("--product-warehouse-id cannot be used on level 2")
+		}
+	case levelByProductWarehouse:
+		if productWarehouseID == 0 {
+			return errors.New("--product-warehouse-id is required on level 3")
+		}
+		if productName != "" {
+			return errors.New("--product-name cannot be used on level 3")
+		}
+	default:
+		return fmt.Errorf("unsupported --level=%d (allowed: 1, 2, 3)", level)
+	}
+
+	return nil
+}
+
+func loadReflowRows(
+	ctx context.Context,
+	db *gorm.DB,
+	level int,
+	productName string,
+	productWarehouseID uint,
+) ([]reflowRow, error) {
+	allocSub := db.WithContext(ctx).
+		Table("stock_allocations sa").
+		Select(`
+			sa.stockable_id,
+			COALESCE(SUM(sa.qty), 0) AS used_qty
+		`).
+		Where("sa.stockable_type = ?", fifo.StockableKeyPurchaseItems.String()).
+		Where("sa.status = ?", entity.StockAllocationStatusActive).
+		Where("sa.deleted_at IS NULL").
+		Group("sa.stockable_id")
+
+	calcSub := db.WithContext(ctx).
+		Table("purchase_items pi").
+		Select(`
+			pi.product_warehouse_id,
+			COALESCE(SUM(pi.total_qty), 0) AS sum_total_qty,
+			COALESCE(SUM(COALESCE(alloc.used_qty, 0)), 0) AS sum_allocated_qty,
+			COALESCE(SUM(COALESCE(pi.total_qty, 0) - COALESCE(alloc.used_qty, 0)), 0) AS computed_qty
+		`).
+		Joins("LEFT JOIN (?) alloc ON alloc.stockable_id = pi.id", allocSub).
+		Where("pi.product_warehouse_id IS NOT NULL").
+		Group("pi.product_warehouse_id")
+
+	query := db.WithContext(ctx).
+		Table("product_warehouses pw").
+		Select(`
+			pw.id AS product_warehouse_id,
+			pw.product_id AS product_id,
+			p.name AS product_name,
+			COALESCE(pw.qty, 0) AS current_qty,
+			calc.sum_total_qty,
+			calc.sum_allocated_qty,
+			calc.computed_qty
+		`).
+		Joins("JOIN products p ON p.id = pw.product_id").
+		Joins("JOIN (?) calc ON calc.product_warehouse_id = pw.id", calcSub).
+		Order("pw.id ASC")
+
+	switch level {
+	case levelByProductName:
+		query = query.Where("LOWER(p.name) = LOWER(?)", productName)
+	case levelByProductWarehouse:
+		query = query.Where("pw.id = ?", productWarehouseID)
+	}
+
+	rows := make([]reflowRow, 0)
+	if err := query.Scan(&rows).Error; err != nil {
+		return nil, err
+	}
+
+	return rows, nil
+}
+
+func modeLabel(apply bool) string {
+	if apply {
+		return "APPLY"
+	}
+	return "DRY-RUN"
+}
+
+func levelLabel(level int) string {
+	switch level {
+	case levelAll:
+		return "all product_warehouse from purchase_items"
+	case levelByProductName:
+		return "specific product name"
+	case levelByProductWarehouse:
+		return "specific product_warehouse_id"
+	default:
+		return "unknown"
+	}
+}
+
+func nearlyEqual(a, b float64) bool {
+	return math.Abs(a-b) <= qtyEpsilon
+}