Supplier On-Time Delivery Calculator

About the Supplier On-Time Delivery Calculator

On-time delivery (OTD) rate is the most widely used supplier performance metric. It measures the percentage of deliveries received on or before the promised date. A high OTD rate (95%+) indicates a reliable supplier who supports smooth production operations; a low OTD rate creates planning uncertainty, excess safety stock, and potential production disruptions.

OTD is typically tracked monthly by supplier and reported on supplier scorecards. It can be measured by purchase order line, by delivery, or by quantity — each method provides a slightly different perspective on performance.

This calculator computes the OTD rate from total deliveries and on-time deliveries, along with the number of late deliveries and their impact on your operations.

Integrating this calculation into regular operational reviews ensures that key decisions are grounded in current data rather than outdated assumptions or rough approximations from the past. Precise measurement of this value supports data-driven planning and helps manufacturing professionals make informed decisions about resource allocation and process optimization strategies.

When This Page Helps

OTD is the foundational supplier performance metric. Without reliable delivery, even the best price and quality are undermined. Tracking OTD builds data for supplier scorecards, corrective actions, and sourcing decisions.

How to Use the Inputs

1. Enter the total number of deliveries in the measurement period.
2. Enter the number of deliveries received on or before the promised date.
3. Optionally enter the cost impact of each late delivery (expediting, overtime, etc.).
4. Review the OTD percentage and late delivery count.
5. Compare to your target (typically 95% or higher).
6. Share results with the supplier as part of the scorecard process.

Example Calculation

Tips & Best Practices

• Define "on-time" clearly: does the delivery window include early deliveries?
• Track OTD at the PO line level for the most granular view.
• Include OTD in supplier scorecards with minimum thresholds for continued business.
• Investigate chronic late deliveries — root causes often include capacity issues or poor scheduling.
• Early deliveries can also be problematic (storage cost, cash flow) — consider a delivery window.
• Automated receipt tracking in ERP provides the most accurate OTD data.

OTD Measurement Methods

PO Line OTD counts each line item independently — a PO with 5 lines where 4 arrive on time scores 80%. Delivery OTD treats the entire shipment as one event — all lines must be on time for the delivery to score as on-time. Quantity OTD measures units — 950 of 1,000 ordered units arriving on time is 95% regardless of how many deliveries it took.

OTD in Supplier Scorecards

Most supplier scorecards weight OTD between 20-40% of the total score, alongside quality, price, and responsiveness. OTD data should be reviewed with the supplier at least quarterly, with clear expectations for improvement when performance falls below target.

Connecting OTD to Inventory

Poor OTD directly increases safety stock requirements. If a supplier's OTD drops from 98% to 90%, you need more buffer stock to compensate for the unpredictability. Improving OTD is often the most cost-effective way to reduce safety stock.

Frequently Asked Questions

• What is a good OTD rate?

  World-class OTD is 98%+. Most companies target 95% as a minimum acceptable level. Below 90% indicates a significant reliability problem that should trigger corrective action.

• Should early deliveries count as on-time?

  It depends on your definition. Some companies count early deliveries as on-time; others define a delivery window (e.g., ±2 days) and count only deliveries within that window. Early deliveries can create storage and cash flow problems.

• How often should I measure OTD?

  Track every delivery and report monthly. Quarterly or annual summaries are useful for trend analysis and supplier reviews, but monthly reporting enables timely corrective action.

• What causes poor OTD?

  Common causes include supplier capacity constraints, poor production scheduling, transportation delays, unrealistic lead time commitments, and demand volatility that causes rush orders. Monitoring trends in this area over successive periods will highlight improvement opportunities and confirm whether changes are producing the desired effect.

• How do I improve a supplier's OTD?

  Share performance data transparently, conduct root cause analysis for late deliveries, provide better demand forecasts, align on realistic lead times, and consider alternative shipping methods. Running this calculation with a range of plausible inputs can help you understand the sensitivity of the result and plan for different scenarios.

• Should I measure OTD by line or by delivery?

  By PO line is more granular and catches partial delivery issues. By delivery (entire shipment) is simpler. By quantity measures the volume impact. Choose the method that best reflects your operational impact.