Glossary
What is supplier on-time delivery? How to measure it honestly
Supplier on-time delivery: Supplier on-time delivery is the share of purchase order lines a supplier delivers by the promised date, measured from your own receipts.
On-time delivery = lines received on or before the promised date / lines due in the period
By Roufaida Bouchamha, founder
The definition
Supplier on-time delivery (OTD) measures how reliably a supplier keeps its dates. It is usually calculated per order line, over a month or a quarter, from the promised date and the receipt date recorded in your ERP. Some companies also measure in-full (the right quantity), which together gives on time in full.
How to measure it from your own data
- Export receipts for the period with, for each line, the promised date, the receipt date and the quantities.
- Decide your tolerance: on time can mean on the promised date, or within a window such as two days early to zero days late.
- Count lines received within the window and divide by lines due in the period.
- Measure by supplier, and for important suppliers by part family.
Which date to measure against
- The first confirmed date shows how reliable the supplier's original commitment was.
- The latest promised date shows whether the supplier keeps the dates it updates.
Measuring only against the latest date can make a supplier look reliable while it moves every date once or twice. Keep both.
Illustrative example, not a customer result
A supplier had 40 lines due last quarter. 30 arrived by their first confirmed date: 75%. 37 arrived by their latest promised date: about 93%. The gap means dates were moved often, which matters for planning even if final dates were mostly kept.
What on-time delivery does not tell you
A supplier at 95% can still stop your line if the 5% late lines are on parts with no cover. For daily decisions, rank late lines by the stock risk behind them (see chase list); use on-time delivery for the supplier review.
How WERISCO uses it
WERISCO shows supplier lead-time drift and ranks late or undated orders by severity, with each part's days of cover shown as evidence. It does not predict supplier delays; your team decides. Nothing is written back to your ERP and nothing is sent to suppliers.
Questions people ask
- Is on-time delivery the same as OTIF?
- No. OTIF also requires the full quantity. A line that arrives on time but short counts as on time but not in full.
- How long a period should I use?
- Monthly for monitoring and quarterly for supplier reviews, so that a few lines do not swing the result too much.
- Should early deliveries count as on time?
- Decide with your team. Very early deliveries add stock and can be a problem; many companies use a window that limits early arrivals.
