Supply Chain Fill Rate Estimator
Optimize inventory levels to meet service level agreements (SLA) and fill rate targets. Enter values for instant results with step-by-step formulas.
Frequently Asked Questions
What is service level in supply chain?
Service level is probability of not stocking out during lead time. 95% service level = 95% of replenishment cycles have no stockout, 5% experience stockout. Example: Order placed every 2 weeks (26 cycles/year). 95% service = stockout 1.3 times/year. Higher service (99%) = more safety stock = higher inventory cost. Lower (90%) = less inventory but more stockouts (lost sales, customer dissatisfaction). Balance: inventory cost vs. stockout cost. Industry varies: Walmart targets 98-99% (customer expectation high), B2B components may accept 90-95% (customers tolerate backorder).
What is fill rate vs. service level?
Service level: % of cycles without stockout (yes/no binary). Fill rate: % of units demanded that are immediately available. Example: Customer orders 100 units, you have 95 in stock. Fill rate = 95%. Service level = 0% (stockout occurred). Fill rate is stricter: partial fulfillment counts as failure for service level but 95% for fill rate. Target: Fill rate 95-99% (immediate availability). Measure both: Service level (cycle-based), fill rate (unit-based).
How do I improve fill rate without increasing inventory?
Options: (1) Reduce lead time (faster replenishment = less buffer needed), (2) Improve forecast accuracy (lower demand variance = less safety stock), (3) Consolidate SKUs (fewer variants = focused inventory), (4) Postponement strategy (finish-to-order for final customization), (5) Supplier collaboration (VMI, consignment), (6) Safety stock pooling (centralized vs. distributed). Example: Reduce lead time 30 → 20 days, safety stock drops 25% (same service level). Or improve forecast accuracy (demand σ 20 → 15), safety stock drops 20%.
How do I verify Supply Chain Fill Rate Estimator's result independently?
The Formula section on this page shows the equation used. You can reproduce the calculation manually or in a spreadsheet using those steps. Compare your answer against the worked examples in the Examples section, which use known reference values so you can confirm the calculator is behaving as expected.
What inputs do I need to use Supply Chain Fill Rate Estimator accurately?
Each field is labelled with the required unit (metric or imperial). Gather your source values before starting — for example, a weight measurement in kilograms, a distance in metres, or a dollar amount — and enter them exactly as measured. The formula section on this page lists every variable and explains what each represents.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.