Use a flat rate book for work you can write down before you see the house. Estimate the job when you cannot. That is the whole rule, and here is the money in it: the BLS producer price index for construction materials rose 10.1% between August 2025 and August 2026. A book you priced last January is running about 8% light on every part number in it, and nothing told you. On a $600 book line at the 6.3% net margin NAHB reports for remodelers, you were clearing $37.80. Materials at 40% of that price have quietly taken $19 of it. Flat rate pays you when the variance sits in your hours. It bleeds you when the variance sits in the scope.
What is the difference between flat rate pricing and estimating each job?
Both hand the customer a fixed number. The difference is when you set that number and how much you knew at the moment you set it.
A flat rate price is decided before the job exists. You build a book once — one price per task, parts and labor and margin already folded in — and every customer who asks for that task gets that number. An estimate is decided after you have stood in the specific house.
Flat rate prices from a category. An estimate prices from an address.
There is a third option people lump in here, which is billing time and materials. That moves the overrun risk onto the customer and hands them a bill they did not agree to. It survives in a few trades and almost nowhere in residential remodeling, because homeowners will not sign an open number.
When does flat rate pricing make you more money?
When the task is repeatable enough that your hours are predictable, and the variation lives in your crew rather than in the building.
A task belongs in the book when:
- You have done it more than about twenty times.
- You can state the scope on the phone without asking what year the house was built.
- The parts list does not change from address to address.
- Your slowest competent tech finishes inside the same window as your fastest.
Miss the last one and the book is priced for a person who might not be working that day.
The real payoff is not the price. It is that the argument about hours disappears. Customers argue about hours. They do not argue about a number they already agreed to, and a technician who is not defending his hours is a technician who finishes the job and leaves. A book price is also the same at 6pm on a Saturday as it is on a Tuesday morning, which stops your crew from discounting their way out of a house.
When does a flat rate book lose money?
Two ways. The second one is worse, because it is silent.
The job runs long. Start with what an hour actually costs you.
| Step | Figure |
|---|---|
| Median carpenter wage (BLS, May 2025) | $29.12/hr |
| Wages are 70.0% of total compensation (BLS ECEC, June 2026), so loaded cost | $41.60/hr |
| Paid hours in a year | 2,080 |
| Hours that land on a billable job | 1,500 |
| Cost per billable hour, before any overhead | $57.69/hr |
Now put that against the $600 book line clearing $37.80. One hour of overrun costs $57.69. The line goes from making $37.80 to losing $19.89.
Read that again, because it is the single most useful number on this page. A book line priced at industry-average net survives about forty minutes of overrun. Forty minutes. That is your entire cushion, and it is why the book has to be priced at your slowest competent tech's hours rather than your best guy's.
The book goes stale. Nobody reprices a book monthly. Meanwhile materials moved 10.1% in twelve months and 8.1% since January. On a line that is 40% parts, an 8% material increase eats $19 of a $37.80 margin without a single thing going wrong on the job site. You will not feel this one. It does not show up as a bad day; it shows up as a year where you were busy and the account never grew.
Then there are old houses. A 40-gallon water heater swap is a clean book line until the house is a 1968 ranch, the supply is galvanized, there is no shutoff at the tank, and the flue does not meet current code. Same book line. Completely different job.
The shops that handle this well put the condition in the book as its own price. "Water heater replacement — pre-1980 supply" is a separate line at a separate number, and the tech carries a one-page form that decides which line applies before he opens the truck. The shops that handle it badly absorb the difference and call it the cost of doing business.
How do you price a book line?
From your own burdened cost. Never from what the shop across town charges.
Copying a competitor's book is the most common way this gets done and it is close to worthless, because you have no idea what his wage bill, his truck count or his overhead look like. Match his price with a worse cost base and you have bought yourself more call volume and the same bank balance in December. That outcome is common enough that it deserves its own warning: square-foot and flat pricing both fail the same way on small jobs, because fixed costs do not scale down.
The order that works: get your burdened hourly cost first, then your overhead per hour, then apply the margin you actually need. Pricing labor properly is the step everyone skips, and skipping it makes every line in the book wrong by the same amount.
Can you run both at once?
Yes, and most shops that make real money on flat rate do exactly that.
| Job | Method | Why |
|---|---|---|
| Diagnostic or service call | Flat fee | The scope is one hour of looking |
| Water heater swap, house under 25 years old | Book | Known before arrival |
| Toilet or faucet replacement | Book with a minimum | Small, repeatable, fixed parts |
| Drywall patch under 4 feet | Book with a minimum | Travel dominates the cost |
| 200-amp panel upgrade | Estimate | Permit and utility scope varies by address |
| Any bathroom or kitchen remodel | Estimate | Scope is discovered behind the tile |
The dividing line is the same every time. Can you write the scope down before you see it? Book it. Otherwise walk it.
What this misses
The $57.69 is a national median carrying a lot of weight. Carpenter wages vary by close to a factor of two between metros, so run this with your own payroll before you trust it.
The 30% benefit burden is the private-industry average across all industries, not construction specifically. Construction generally runs higher, because workers' comp on a high-risk class code is not comparable to an office. Treat $57.69 as a floor.
PPI measures what producers charge, not what your supply house charges you. The direction is reliable. The exact 10.1% is not your number.
One legal point that gets missed. A flat rate price handed over in writing is not a ballpark — in California, a home improvement contract over $500 must state the total contract price under Business and Professions Code 7159, and that number is the one you are held to. Which method you used to arrive at it is your problem, not the customer's. The distinction between an estimate, a quote and a bid decides whether you can revise it later, and most contractors find out which one they handed over during the argument.
Where this actually breaks for most small shops is not the method. It is that the estimates take too long, so everything gets forced into a book that should not be in one. BidWalk exists for the other half of that problem — pricing a job properly from the walkthrough, fast enough that you were never tempted to guess.
