Backorder Rate Calculator
Calculates the percentage of ordered units that could not be fulfilled from available stock and were placed on backorder. Use it to monitor service levels, identify chronic stockouts, and justify safety stock investments.
About this calculator
Backorder Rate measures the proportion of customer orders that cannot be shipped immediately due to insufficient inventory. The formula is: Backorder Rate = (Backordered Units / Total Ordered Units) × 100. A high backorder rate signals that your inventory replenishment or demand forecasting is not keeping pace with customer demand. Even a rate of 2–5% can significantly damage customer satisfaction and loyalty in competitive markets. The metric is most meaningful when tracked over time and broken down by SKU, category, or supplier, so you can target the specific products causing the most service failures. Complementary metrics include fill rate (the inverse perspective) and order cycle time. Reducing backorder rate typically requires improving safety stock calculations, lead time reliability, or demand forecasting accuracy.
How to use
Suppose a warehouse received 2,500 orders in a month but 175 of those units were unavailable and had to be backordered. Step 1 — identify your inputs: Backordered Units = 175, Total Ordered Units = 2,500. Step 2 — apply the formula: Backorder Rate = (175 / 2,500) × 100 = 7%. A 7% backorder rate means roughly 1 in 14 orders experienced a delay due to stockouts. Most retailers target rates below 2%. Enter your own figures to calculate your current backorder rate and benchmark it against industry standards.
Frequently asked questions
What is an acceptable backorder rate for an e-commerce or retail business?
Most e-commerce and retail businesses aim for a backorder rate below 2%, and best-in-class operations often achieve under 1%. Rates above 5% typically indicate a systemic inventory or supply chain problem that is actively costing revenue and customer trust. That said, acceptable rates vary by industry — make-to-order manufacturers may tolerate higher rates than grocery retailers. Tracking the trend over time and comparing to category-level benchmarks is more actionable than any single threshold.
How does a high backorder rate affect customer satisfaction and revenue?
High backorder rates directly erode customer experience because buyers must wait longer than expected for their orders or cancel them entirely. Research consistently shows that stockout experiences push a significant share of customers to competitor sites. Beyond lost immediate sales, backordering damages brand perception and reduces repeat purchase rates. The revenue impact includes not just the deferred sale but also the cost of managing back-orders, expediting shipments, and handling customer service inquiries.
What is the difference between backorder rate and out-of-stock rate in inventory management?
Backorder rate measures the share of ordered units that customers are still waiting for due to stock unavailability — the order is retained and will be fulfilled. Out-of-stock rate, by contrast, measures how often a product is simply unavailable on the shelf or website, regardless of whether a customer places an order. A high out-of-stock rate prevents demand from even registering, while a high backorder rate reflects captured demand that is delayed. Both metrics are important, but backorder rate focuses specifically on fulfillment gaps within confirmed orders.