You open a regular ChatGPT chat and ask for an estimate. You get one. It looks nice. And it's wrong. So you tried AI once, got made-up prices, and quit.
Last updated: October 2026 · By Gen X Still Standing
ChatGPT doesn't know your prices, so it makes some up. Confidently. It doesn't know your deposit, your markup, your dump fee or what you never include, so it leaves them out. It sounds like a bank. And it forgets your business the next time you open it.
The fix isn't a better question. It's giving it your numbers first.
Those "500 prompts" PDFs make you re-explain your business from scratch every time. They get used twice and forgotten. The problem isn't how you ask. It's that the AI has nothing real to work from.
Before AI writes a single estimate, it needs your business on one page: labor rate, minimum charge, markup, dump fee, deposit, payment terms, your common jobs and prices, your warranty, and what's never included.
Here's where most people go wrong. Don't write "it depends." That teaches it nothing, so it will ask you every single time. Write the rule you actually use in your head:
"$75/hr one man, $120/hr two-man crew, 2-hour minimum."
If it really does depend, write what it depends on. Then give it one rule: never make up a price, a measurement or a quantity. If it's not on the page, ask me.
Your customer should only see the final price on each line. In testing, one AI estimate showed "$89 cost + 20% markup" right on the customer's copy. A homeowner who sees your markup starts negotiating your markup.
One page of numbers stops the made-up prices. It doesn't write your change orders, chase your quiet bids or collect the late invoice. And AI can still make mistakes, so read every estimate before it goes out. It's your name on it.
I ran a construction company in Colorado and I did emergency-response hazmat work. I had to close it down. I taught myself AI at 53. On every crew I was ever on, the jobs that went sideways went sideways the same way: somebody guessed. Guessed the measurement, guessed what the customer wanted, guessed the price.
The free Contractor's Leak Finder: slow callbacks, quiet estimates, free extra work, late invoices and missing reviews. What each one costs, a score that tells you how bad it is, and where the numbers come from.
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Can ChatGPT write contractor estimates?
It can write them, but a regular chat doesn't know your prices, so it makes some up. It also leaves out your deposit, markup, dump fee and what you never include.
How do I stop ChatGPT from making up prices?
Give it your business on one page first: rates, minimum, markup, fees, deposit, common jobs and prices. Then tell it to never make up a price, a measurement or a quantity, and to ask you instead.
Will my customer see my markup?
They shouldn't. The customer's copy should show only the final price on each line. Check every AI estimate for cost or markup before you send it.
Can I trust the numbers without checking?
No. AI can still make mistakes. Read every estimate before it goes out. It's your name on it.
What if it still makes something up?
Tell it that's not on your page and to ask you instead. If a price is wrong, fix the page, not the chat.
Educational only. Not legal advice. Contract, lien and collection rules vary by state. You're responsible for reviewing anything AI produces. Results vary and are not guaranteed. Built by a Gen Xer with AI, for Gen Xers.
