A supplier says an order takes ten days, but the production team needs to know when the material will be usable. Lead time is the elapsed time between a defined start and finish. For purchasing, you might measure order release to arrival, or order release to stock cleared for use. Name those events before comparing suppliers or putting a value into a planning system.
The calculation is finish date minus start date, using an agreed calendar and counting rule. Keep supplier transit, warehouse handling, and inspection visible when they explain the difference between arrival and availability. The examples below are hypothetical. Permute publishes this article and sells connected business data and custom applications; its reporting role is separate from purchasing and planning decisions.
Choose the start and finish your decision needs
For an external supplier comparison, order release might be the start and physical receipt the finish. For an internal replenishment review, the start could be an approved material request and the finish the release of inspected stock. Those measures include different work. Keep the labels on the report so a buyer does not attribute internal approval time to the supplier.
Microsoft’s purchase date calculations for Business Central distinguish vendor lead time from inbound warehouse handling and safety lead time. The configured dates serve planning purposes. They should not be confused with timestamps that show when an actual delivery or inspection happened.
- Request to release: shows the time spent preparing and approving the purchase before it reaches the supplier.
- Release to receipt: follows the released order until the material arrives under your chosen receiving definition.
- Receipt to usable stock: captures handling and inspection before production may use the material.
- Release to usable stock: spans the two previous stages when their boundaries meet and do not overlap.
Calculate elapsed days with a stated counting rule
Suppose an order is released on October 1 and arrives on October 11. Inspection finishes on October 13. Using calendar-date subtraction, without counting the start date as a full extra day, release-to-receipt lead time is 10 days. Receipt-to-usable time is 2 days, and release-to-usable lead time is 12 days. This example ignores time of day; use timestamps if that precision changes the decision.
| Measure | Calculation | Result in this example |
|---|---|---|
| Release to receipt | October 11 minus October 1 | 10 calendar days |
| Receipt to usable stock | October 13 minus October 11 | 2 calendar days |
| Release to usable stock | October 13 minus October 1 | 12 calendar days |
If the contract or planning system uses business days, calculate against the applicable work calendar, including holidays. Do not remove weekends from one supplier’s history while leaving them in another’s. Record the time zone when events come from different locations, and decide whether the date represents physical arrival, system entry, or an approved receipt.
Keep a promised date as a separate field. An order received after its promise date can have a short elapsed lead time if it was ordered at short notice. Conversely, a long planned lead time can still result in an on-time delivery. The supplier management software comparison covers the wider performance review; elapsed time and delivery reliability need their own definitions.
Keep partial deliveries at the order-line level
Consider another hypothetical order: 100 units released on October 1, with 60 received on October 11 and 40 on October 16. First-receipt lead time is 10 calendar days and complete-receipt lead time is 15. A quantity-weighted elapsed time would be 12 days: (60 × 10 + 40 × 15) ÷ 100. Each result describes a different aspect of the same delivery.
Use complete-receipt time when the job requires the full quantity before it can start. First-receipt time can describe when any supply becomes available. A quantity-weighted result summarizes the received units, but it can conceal the late balance. Keep the individual receipt lines behind the summary and state which measure the planning review uses.
An open order has no complete-receipt lead time yet. Show its age and outstanding quantity separately rather than dropping it from the report or pretending today is its delivery date. Excluding overdue open orders can make the completed-order average look better while the purchasing team still has a shortage to resolve.
Build a report that explains changes in lead time
Preserve order and line IDs, item and supplier references, ordered quantity, receipt quantity, units, release date, promised date, and actual receipt date. Add inspection release if the measure ends at usable stock. ERPNext’s Procurement Tracker Report is one documented example of reporting procurement references with expected and actual delivery dates. Check which events your own sources record before choosing the report fields.
Group comparable orders. Separate item families, delivery routes, and standard versus expedited service when they change the promise being evaluated. Keep the number of completed lines and the open-order backlog alongside the average. A supplier with a small sample should not receive the same confidence as one with a substantial history of comparable deliveries.
- Does every elapsed time use the same start event, finish event, and day-counting convention?
- Can you distinguish a backdated system entry from the physical receipt it describes?
- Are partial receipts linked to the original order line without duplicating the ordered quantity?
- Are overdue open orders visible beside completed-order statistics?
- Can the planner trace an outlier to its item, route, promise date, and source receipt?
Use the findings as an input to planning review rather than silently replacing a planning parameter with a historical average. The ERP versus MRP article explains how dates affect material requirements. Buyers and planners still decide how supplier variation, order constraints, and approved buffers should affect future orders.
Where Permute fits with purchasing and receiving data
Permute sells connected business data and custom applications. We can scope a recurring report that combines supported sources and supplied purchasing, receiving, and inspection records. Matching the source order and line references comes before calculating elapsed time, and unmatched receipts remain available for review.
Your team defines the date boundaries, calendar, partial-delivery treatment, and which records belong in each comparison. Those definitions can be reused with source evidence and access controls. A buyer can inspect a late line while a planner sees the outstanding quantity and input freshness. The manufacturing dashboard article covers presenting such operational measures with their supporting context.
Inspect the dates behind a supplier report
Start with an available source and identify the order and receipt references your lead-time measure requires.
Keep future purchasing decisions separate from observed history
Permute is not a forecasting engine and does not determine your safety-stock policy. A report does not guarantee a supplier’s next delivery date or authorize a purchase. Missing timestamps remain missing until a responsible owner supplies evidence. Any changes to planning parameters or external purchasing records require a separately verified scope and approval path.
Use a lead-time measure people can reproduce
Calculate lead time between named events using one stated calendar. Separate arrival from stock availability, retain partial receipts, and show open orders alongside completed history. Keep the source dates behind every summary so a buyer can explain a changed result. Use that history in a planning review with the people responsible for future purchasing decisions.
Review a supplier lead-time report
Bring a purchasing export and receipt history, including a partial or overdue delivery your team needs to explain.
Questions about measuring supplier lead time
Is lead time the same as production cycle time?
The labels can refer to different boundaries. A production measure might cover processing within a work center, while purchasing lead time starts when an order is released. Name the actual events and compare them before combining values from different reports.
What should I do with a negative lead time?
Investigate the source dates, time zones, and event definitions. A receipt entered before a later administrative order release may reflect the recording sequence rather than negative physical elapsed time. Keep it as an exception until the owner explains which events the measure should use.
Should canceled orders enter the delivery average?
A canceled order without a receipt does not have a completed delivery duration. Track its cancellation and outstanding history separately. If part of the order arrived, retain those receipt-level observations and label the canceled remainder.
How often should a supplier lead-time report refresh?
Choose a schedule that supports the purchasing review and reflects when sources are updated. Display the extraction time and keep late entries traceable. More frequent refreshes cannot supply a receipt event that has not been recorded.