Foundation 5 of 20 · Schedule
What Is Lead Time? How to Give Customers Realistic Due Dates
Perfect and Late Is Still Late.
"I never miss on quality. Why do I keep missing on dates?" If your work is excellent and your customers keep waiting longer than you said, you have a dates problem, not a quality problem. Here is what lead time is, and how to give customers realistic due dates.
Last Updated: 10/25/2026 · Written by Dr. Paul Borosky, DBA, MBA
The Short Answer
What Is Lead Time?
Textbook Definition
Lead time is the total elapsed time between the placement of a customer order and its delivery, including waiting, queue, processing, and transit time.
In Plain English
Lead time is how long it really takes from the day a customer orders to the day they have it. Not how long the work itself takes. The whole wait, including the time the job sits in line before anyone touches it.
Why It Matters
Why Do Owners Who Never Miss on Quality Keep Missing Dates?
Because they measure the work and never the calendar. A perfectionist will measure a joint three times and never once measure how long a job takes from order to delivery. So they guess, and guesses run short. "A few weeks" becomes ten.
The customer was not measuring the craftsmanship. They were measuring the calendar. On the calendar, perfect and late is just late. The fix is a promise date built from real history, not hope.
Signs you have this problem:
- You quote "a few weeks" or "soon" instead of a date.
- Customers call to ask where their order is.
- Your crew is idle some weeks and buried other weeks.
- You order materials when you get to a job, not when you book it.
- Jobs get worked on in the order that interests you, not the order they are due.
- You have never measured the gap between order date and delivery date.
What It Looks Like
What It Looks Like When "A Few Weeks" Means Ten
From the Fabled Forest · Chapter 5
Blueprint Bella builds the finest furniture in the forest. Doctor Owl's scroll shelf, quoted "a few weeks," was on week eleven and still being sanded because one corner was a hair out. Finished benches for EleWell sat in her shop. A cradle tagged "baby due in January" sat there in late February.
Her crew was playing cards because she had not ordered timber for the mill bridge, which was due before the thaw. Chuck the chipmunk had been quietly tallying on the wall: forty-one idle days since autumn, thirty-three days working past dark.
Doctor Owl found the real dates on three finished jobs: eleven, nine, and ten weeks. Bella had told everyone three. They put up one board, every job sorted by promise date. Bella learned to say "I can't start that until the twentieth." The bridge finished four days before the thaw.
Bella's story is Chapter 5 of Operations for Small Businesses, Book 3 of Dr. Paul's Fabled Forest Business School Series.
The Fix
How to Set Realistic Due Dates in 5 Steps
You need your last few jobs and their dates. That is all the data it takes to start.
Find your real lead time.
Take your last three to five finished jobs. For each, find the order date and the delivery date. Average the gap. That is your real lead time, and it is usually longer than you think.
Give every new job a promise date on the day it is ordered.
Start from your real lead time. Adjust for the size of the job, what is already ahead of it, whether materials are in stock, and who is free to do it.
Add a buffer.
Something always goes wrong. Add a cushion for it, and plan to finish by the buffer date, not the promise date.
Put every job on one board, sorted by promise date.
Not by the order it came in, and not by which one is most interesting. Order materials the day a job goes on the board.
If you cannot meet the date they want, say so on day one.
"I can't start that until the twentieth" is a hard sentence. Saying it on day one beats explaining a late job on day sixty. Good work takes as long as it takes. That is the quality vs. speed trade-off, told honestly.
Dr. Paul's Insight
The second sentence matters most: "I cannot take that one until the twentieth." Owners who cannot say no with a date end up saying yes to everything and delivering everything late. Customers respect a clear date far more than a vague yes. Many will happily wait for a real date. Almost none will happily wait for "soon."
Sample: A Promise Date Board
One board, every job, sorted by promise date. Materials ordered the day a job goes up.
| Job | Ordered | Materials | Finish by (buffer) | Promise date |
|---|---|---|---|---|
| Mill bridge | Jan 5 | Ordered Feb 24 | Mar 10 | Mar 17 |
| Spa benches | Dec 15 | In stock | Feb 26 | Feb 28 |
| Town hall wing | Feb 27 | Order Mar 1 | Jun 1 | Jun 8 |
| Cabinet | Mar 2 | Order Mar 2 | May 4 | May 11 |
Sample for illustration. Use your own average lead time and adjust each job for size and what is ahead of it.
Watch
Video: How to Give Customers Dates You Can Keep
What Is Lead Time? How to Give Customers Realistic Due Dates
Dr. Paul measures real lead time from past jobs and builds a promise date board on screen.
From the Book
Days We Had Nothing to Do
Chapter 5 · Lead Time and Due Dates
Perfect, and Six Weeks Late: A Beaver's Bench
"Chuck," she said slowly. "What are those?"
The chipmunk turned around. He moved the screws to one cheek so he could talk.
"Days we had nothing to do," he said, around them. "Since the autumn." He looked at the board. "Forty-one."
What was on the other side of Chuck's board, and what did Bella's real lead time turn out to be? Find out in Chapter 5. Book 3 of Dr. Paul's Fabled Forest Business School Series.
Get the Book on Amazon →FAQ
Lead Time Questions
What is the difference between lead time and due date?
How do I calculate lead time?
What is a promise date?
How much buffer should I add to a due date?
Keep Going
Related Foundations
Lead time connects four foundations that decide when work actually gets done. New to a term on this page? Every one is in the operations glossary.
Foundation 7 · Capacity
Lead time grows when demand runs past your capacity.
Foundation 8 · Capacity Planning and Booking
A booking limit keeps the board from overloading.
Foundation 15 · Hand-Offs and Order Tracking
Track every job on one board everyone can see.
Foundation 13 · The Run Sheet
For events and big days, turn the dates into a run sheet.
Written by Dr. Paul Borosky, DBA, MBA, business consultant and author who helps owners build businesses that run on systems. Want help building a schedule your customers can count on? See fractional COO services.
This page is for general educational purposes only. It is not legal, safety, employment, financial, or tax advice. Safety and employment rules differ by place and industry. Dollar figures are illustrations. The Fabled Forest and its characters are fictional. For decisions about your own business, consult a qualified professional.