Supplier on-time delivery (OTD) is the share of order lines a supplier delivers by the date it confirmed, measured at your receiving dock.
OTD % = lines received on time ÷ total lines due in the period × 100
Before you calculate anything, write down three rules: which date counts as the promise (the first date the supplier confirmed), what counts as on time (for example, no days late and up to 2 days early), and when an arrival counts (the date it is booked in at your dock, not the date it shipped). A common starting target for direct materials is 95%, tighter for line-stopping parts and looser for MRO items you can buy from several sources.
This guide covers the formula and its edge cases, the few extra metrics worth tracking, a tracking log and scorecard you can copy, how to judge a new supplier's delivery capability before you award, how to find out why deliveries are late, and contract wording that makes the numbers count.
What late deliveries actually cost
Most of the cost of a late supplier never shows up on that supplier's invoice. Put a number on it before you start a conversation, because "you were late 18 times" lands differently from "your late deliveries cost us about $12,000 this year".
Illustrative example: you buy $420,000 a year from a supplier across 200 PO lines, and it runs at 82% OTD, so 36 lines arrive late.
| Cost | Assumption | Annual cost |
|---|---|---|
| Premium freight | 10 late lines expedited at about $350 extra each | $3,500 |
| Line downtime | 2 stoppages × 4 hours × 6 operators × $40/hour loaded | $1,920 |
| Extra safety stock | 2 extra weeks of a part used at $8,000/week = $16,000 held, at an assumed 25% annual carrying rate | $4,000 |
| Chasing and rescheduling | 36 late lines × 1.5 hours × $45/hour | $2,430 |
| Total | $11,850 |
That is 2.8% of spend on top of the price ($11,850 ÷ $420,000). A competing supplier that quotes 2% higher but delivers reliably can be the cheaper one. Lost customer orders and late-delivery penalties from your own customers come on top and are harder to price, so leave them out of the number and mention them separately.
How to calculate on-time delivery rate
The formula is simple. The definitions are where teams disagree, so settle these before the first report.
| Definition | Counts as on time | Use it when |
|---|---|---|
| Must arrive by | Any arrival on or before the confirmed date | Early stock is harmless and you have the space |
| Delivery window | Inside a set range, e.g. 2 days early to 0 days late | Most direct materials. Early arrivals clog receiving or tie up cash |
| Exact date or time slot | On the confirmed day, or inside the booked dock slot | JIT lines, perishables, cross-dock operations |
Line level vs order level. Line-level OTD scores each PO line on its own. Order-level OTD counts a PO as on time only if every line arrived on time. Report line level to see where the problem is, and order level when you need complete kits to build.
Illustrative example: in Q3 a supplier had 20 POs with 48 lines due. Your window is 2 days early to 0 days late. 41 lines arrived inside the window, 4 arrived late and 3 arrived more than 2 days early.
- Line-level OTD = 41 ÷ 48 = 85.4%
- Late lines only (ignoring early) = 44 ÷ 48 = 91.7% on time or early
- Order level: 15 of the 20 POs had every line inside the window, so 15 ÷ 20 = 75%
The same supplier can be reported as 75%, 85% or 92%. Pick one definition, print it on the scorecard and use it for every supplier.
Rules that keep the number honest:
- Measure against the first date the supplier confirmed. Only a change you asked for (new quantity, new date, a spec change) resets it. A date the supplier pushes out is still late against the original.
- Count partial shipments as late until the full quantity arrives, or track them as "on time, not in full" with OTIF (below).
- Use your receipt date, not their ship date. If you buy ex works and arrange freight yourself, also track ship-on-time so carrier delays are not blamed on the supplier.
- Score lines with no confirmed date against your requested date, and push the supplier to confirm every PO within 2 business days.
- Track committed-date OTD and requested-date OTD separately. The first shows whether the supplier keeps promises. The second shows whether its lead times fit your needs.
The other delivery metrics worth tracking
OTD alone hides how late the late lines were and how predictable the supplier is. Add only what you will act on.
| Metric | Formula | What it tells you |
|---|---|---|
| OTIF (on time in full) | Lines on time and in full quantity ÷ total lines | Whether you can actually build or ship. Often 5 to 10 points below OTD for suppliers that short-ship |
| Average days late | Sum of days late ÷ number of late lines | 1 day late and 3 weeks late both count as "late" in OTD |
| Lead time variability | Standard deviation of actual lead times | How much safety stock or buffer time you need |
| Early delivery rate | Lines early beyond your window ÷ total lines | Whether "on time" is being bought with early shipments |
| Perfect order rate | Orders on time, in full, undamaged, with correct paperwork ÷ total orders | Overall reliability, useful for strategic suppliers |
| PO confirmation rate | POs confirmed with a date within 2 business days ÷ POs sent | An early warning: suppliers that do not confirm tend to deliver late |
Illustrative example of lead time variability: a supplier quotes 10 days. The last 8 deliveries took 9, 10, 12, 10, 15, 11, 10 and 13 days. The average is 90 ÷ 8 = 11.25 days and the sample standard deviation is about 2.0 days. Plan on 11 to 12 days, not 10, and if you want to cover nearly every delivery, plan on the average plus two standard deviations, about 15 days. A supplier at a steady 12 days is easier to plan around than one averaging 10 with a 4-day spread.
Setting OTD targets
Set targets by how much a late delivery hurts, not by a published industry figure. The table below gives common starting points. Adjust them to your own operation.
| Item type | Starting target | On-time window | Review |
|---|---|---|---|
| Line-stopping, single-source or JIT parts | 98% or higher | 0 days late, at most 1 day early | Monthly |
| Standard direct materials with safety stock | 95% | 0 days late, up to 3 days early | Monthly or quarterly |
| MRO and indirect items with several sources | 90% | Up to 2 days late | Quarterly |
| Project and site deliveries | Each delivery judged against the site need date | Agreed per project | Each project milestone |
If a supplier is far below target today, a jump straight to 95% is not a plan. Measure 3 months to get a baseline, then step up.
Illustrative example: baseline 81%, required 95%. Set 88% for next quarter and 95% for the quarter after, and tie the corrective actions below to those dates. If the supplier hits 88% but stalls, look at capacity or lead time rather than pushing harder.
Judging a supplier's on-time delivery capability before you award
The cheapest late delivery is the one you avoid at sourcing. When you request quotes for anything time-critical, ask for:
- Quoted lead time per item and what it assumes. From stock, make to order, or waiting on raw material. A 2-week lead time that assumes stock is a 6-week lead time when stock runs out.
- Their own OTD record. Their last 12 months of on-time delivery to customers and how they measure it (ship date or customer receipt, which window).
- Capacity. Current load on the line or cell that would make your part, and what happens to lead time if your volume doubles.
- Long-lead inputs. Which raw materials or components they buy in, the sub-supplier lead times, and whether they hold safety stock of them.
- Order confirmation practice. Whether they confirm every PO with a date, and how quickly.
- Shipping lane. Carrier, transit time to your dock, and who arranges freight under the quoted Incoterm.
Then check it. Ask a reference customer what OTD they see, place a trial order, and score the first 3 months against the date they confirm. Weigh the answers next to price when you award: a supplier that is 3% cheaper but cannot show any delivery record is a risk you are choosing to take.
Finding out why deliveries are late
Asking a supplier to "do better" changes nothing. Code every late line with a reason, find the biggest cause, and fix that.
| Root cause | What the data shows | Fix |
|---|---|---|
| Capacity | Late lines bunch at month or quarter end, or on large orders | Longer quoted lead time, split orders, volume moved to a second source |
| Quoted lead time too short | Late by a steady 3 to 5 days on most lines | Re-quote the lead time and plan to the real figure |
| Raw material shortages | Lateness follows a specific material or sub-supplier | Supplier holds buffer stock, or you share a forecast earlier |
| Your own changes | Lines late after you changed quantity, date or drawing | Freeze window (for example, no changes inside 2 weeks), reset dates only for your changes |
| Forecast surprises | Late when your order is well above recent run rate | Share a rolling 3-month forecast, set a monthly volume band |
| Carrier or customs | Shipped on time, arrived late | Separate ship-on-time from transit, change carrier or Incoterm |
| PO errors and missed confirmations | Late lines with no confirmation or a wrong part number | Confirm every PO within 2 days, check part numbers and drawings on the PO |
A simple root cause routine
- Week 1, buyer: pull the last 90 days of late lines with PO, item, confirmed date, receipt date and days late.
- Weeks 1 to 2, buyer and supplier: agree a reason code for each line. The supplier often knows the reason but has never been asked.
- Week 2, buyer: sort reasons by count and by cost. Usually one or two causes account for most of the lateness.
- Week 3, buyer, planner and supplier account manager: a 1-hour review of the top causes. Ask "why" until you reach something one side can change. "Late" becomes "the press was busy", which becomes "your orders arrive in month-end batches and fill the same week".
- Same meeting: write each corrective action with an owner and a date.
- The next 8 to 12 weeks, buyer: re-measure monthly. If OTD does not move, the cause was wrong. Go back to step 2.
A delivery tracking log and scorecard you can copy
You need one row per PO line. A shared spreadsheet works for a few dozen suppliers.
| PO | Line | Supplier | Item | Qty ordered | Requested date | Confirmed date | Changed by buyer? | Receipt date | Qty received | Days late | On time? | In full? | Reason code |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4512 | 1 | Supplier A | Bracket 220 | 500 | 3 Sep | 5 Sep | No | 9 Sep | 500 | 4 | No | Yes | Capacity |
| 4512 | 2 | Supplier A | Bracket 240 | 300 | 3 Sep | 5 Sep | No | 5 Sep | 260 | 0 | Yes | No | Short ship |
Days late = receipt date minus confirmed date. "On time?" applies your window. OTD, OTIF and average days late all come from these columns, so do not track them anywhere else.
Each month, roll the log up into a one-page scorecard per supplier:
| Measure | Target | This month | Last 3 months | Trend |
|---|---|---|---|---|
| OTD (line level) | 95% | 88% | 84%, 86%, 88% | Improving |
| OTIF | 92% | 81% | 78%, 80%, 81% | Flat |
| Average days late | 2 or fewer | 4.1 | 5.0, 4.6, 4.1 | Improving |
| Top reason code | Capacity (6 of 9) | |||
| Open actions | Second shift on press 3, due 30 Nov |
Review cadence: monthly for suppliers below target or on an improvement plan, quarterly for key suppliers that are on target, and once a year for the rest. Send the scorecard a few days before the meeting so the supplier arrives with answers, not excuses.
Common tracking mistakes
- Measuring against your requested date only. The supplier never agreed to it. Track both, and judge reliability on the confirmed date.
- Letting the supplier reset the date. OTD looks great while your line waits. Only buyer-initiated changes reset it.
- Using ship date. Measure at your dock, and track ship-on-time separately if you own the freight.
- One blended number for all suppliers. Report by supplier and by item type. A 93% average can hide one supplier at 70%.
- Measuring without consequences. If a supplier at 75% for six months still gets the same volume, the scorecard is a report, not a tool.
Contract terms: late delivery clauses and incentives
Put the definition and the remedy in the contract or PO terms, so nobody argues about either later. Example wording to adapt with your lawyer:
"Supplier shall deliver each PO line in full by the Confirmed Delivery Date, being the date Supplier confirms in writing within two (2) business days of receiving the PO. For each full business day a line is late, Supplier shall credit Buyer [0.5]% of that line's value, up to a maximum of [5]% of the line's value. Delays caused by Buyer changes or force majeure are excluded. Credits will be applied against the next invoice. If Supplier's monthly on-time delivery, measured as defined in Schedule [X], is below [90]% for two consecutive months, Supplier shall provide a written corrective action plan within ten (10) business days, and Buyer may move volume to other suppliers."
Illustrative example: a $12,000 line arrives 4 business days late, so the credit is 4 × 0.5% = 2% = $240. A line 15 days late would be 7.5%, but the cap holds it at 5% = $600.
Points to check:
- Keep credits close to your real cost. In many jurisdictions a fixed late-delivery charge has to be a reasonable estimate of loss (liquidated damages), not a punishment, or it may not be enforceable.
- Cap it. Suppliers price unlimited exposure into the quote or refuse the term.
- Enforce it. A credit you never claim teaches the supplier the clause is decoration. If you waive it, waive it in writing as a one-off.
- Pair it with incentives. Rewards for reliable suppliers often change behavior faster than credits: more volume or a longer agreement for suppliers above target for 2 straight quarters, first look at new parts, or a reduced inspection level.
Where AuraVMS fits
AuraVMS is an RFQ and supplier tool. Quotes come back in one format, including the lead times and delivery dates suppliers commit to, so you can compare them side by side and see supplier performance comparison next to price when you award. Orders are placed from the winning quote in one click. On the Medium Team plan you can send reminders to suppliers and export complete data to Excel, which is a practical way to feed the tracking log above. Receipt dates and reason codes still come from your receiving process.
Related guides
Frequently asked questions
What is supplier on-time delivery capability?
It is a supplier's ability to hit the dates it confirms, consistently, at the volumes you need. Judge it on evidence: OTD over the last 6 to 12 months, how widely its actual lead times vary, spare capacity on the line that makes your part, how it secures long-lead materials, and whether it confirms every PO with a date. For a new supplier, ask for its own OTD report and reference customers, then score a trial order.
What is a good on-time delivery rate for suppliers?
95% at line level is a common target for direct materials. Line-stopping or single-source parts usually need 98% or more. MRO items with several sources can sit around 90%. What matters more is that the definition (date, window, line or order level) is fixed and the same for every supplier.
What is the difference between OTD and OTIF?
OTD only checks timing. OTIF counts a line as a success only if it arrived on time and in the full quantity ordered. If a supplier often short-ships, OTIF will be well below OTD, and OTIF is the one that matches what your production line sees.
Do early deliveries count as on time?
Only if your definition says so. Most teams allow a few days early (for example, up to 2 or 3) and count anything earlier as a miss, because early stock takes space and cash. Tell suppliers the window in writing.
Should we measure against the committed date or the requested date?
Track both. Committed-date OTD shows whether the supplier keeps its promises. Requested-date OTD shows whether its lead times fit your plan. A supplier strong on the first and weak on the second has a lead time gap, not a reliability problem.
How do we handle suppliers who blame the carrier?
If the supplier arranges freight (delivered Incoterms such as DAP), carrier delays are the supplier's to manage, and they count. If you arrange freight, track ship-on-time separately so you can see whether the goods left on time. Repeated carrier delays point to the wrong carrier or too little transit time in the quoted lead time.
How do we track delivery performance for overseas suppliers?
Split the lead time into production, port to port and customs and inland, and record dates for each leg (ready date, departure, arrival at port, receipt). Score the supplier on ready or ship date against its confirmation, and score the total against your need date. Build lead time buffers from the actual spread you measure, not the quoted transit time.
Stop managing supplier delivery problems through spreadsheets and email chains. AuraVMS tracks delivery commitments from RFQ through fulfillment, automatically calculates performance metrics, and gives you the data foundation to drive supplier improvement. Start your free 14-day trial at auravms.com.