Lead Time Calculator
Calculate total order lead time across processing, production, and delivery stages, and see how variability drives the safety buffer customers actually experience.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Lead Time Calculator | — | Total lead time = order processing + queue + production + shipping | days |
Step-by-Step Examples
Processing 1.5, queue 4, production 3, shipping 5 days, 2.5 day SD, 95% service target.
- Total = 1.5 + 4 + 3 + 5 = 13.5 days
- Largest component: shipping at 5 days (37%)
- Value-added share = 3 / 13.5 = 22.2%
- At 95% service: quote 13.5 + 1.65 × 2.5 = 17.6 days
Processing 1, queue 12, production 2, shipping 3.
- Total = 18 days
- Queue is 67% of total lead time
- Value-added share only 11.1%
- Reducing queue time is the largest available lever
Total 10 days with 4 day standard deviation, 99% service target.
- Buffer = 2.33 × 4 = 9.3 days
- Quoted lead time = 19.3 days
- Variability nearly doubles the promise despite a 10 day average
Real-World Applications
Common Mistakes to Avoid
Quoting the average means missing the promise roughly half the time. A buffer sized to variability is what delivers reliable on-time performance.
Production is frequently a small share of total lead time. Attacking queue and processing usually yields far larger reductions.
Reducing variability often improves customer experience more than reducing average lead time, because it shrinks the buffer needed.