The Estimate You Gave in Your Head Is Costing You Real Money
"About four hundred for that, I'd say."
You said it on the phone while walking to your car. Quick mental arithmetic. Similar to the Wilson job from last month, maybe a bit smaller. Four hundred felt right.
Three weeks later, you've spent six hours on it. Materials came in higher than you remembered. The client needed changes you didn't anticipate but couldn't really charge for — they weren't unreasonable, just not what you'd pictured.
Your actual cost: closer to six-fifty. But you're not going to invoice £650 when you said £400. So you eat it.
This happens more than you think. Not every job. But enough.
The problem with gut-feel pricing
Gut feel works brilliantly when the variables are stable. Same type of work, same materials, same kind of client, same scope. Your brain pattern-matches and lands close enough.
But variables drift. Quietly.
Timber costs shifted 15% and you didn't update your mental model. Your average project complexity crept up as you started taking on bigger clients. You got faster at some tasks and slower at others. That one supplier you used to rely on now takes three days longer, which means you're paying for expedited shipping half the time.
Your gut doesn't track any of this. It's still running on 2022 data.
The jobs that hurt you are the ones you think you know
New work gets more attention. Unfamiliar scope, unfamiliar client — you slow down. You write things out. You think about what could go wrong.
But the bread-and-butter jobs? The ones you've done a hundred times? Those get the quick estimate. The mental arithmetic. The "yeah, about four hundred" while you're unlocking the car.
Except those are exactly the jobs where small margin erosion compounds. You do fifty of them a year. If you're underpricing by 12% on average, that's six jobs you're essentially doing for free.
What changes when you actually look
I worked with a contractor who quoted kitchens the same way for years. In his head, he had a rough formula: base cost plus time plus a margin. Felt solid.
When we actually tracked his last twenty kitchen jobs — real hours, real materials, real margin — he found three things:
- His average was fine. Across all twenty jobs, his gut was pretty close.
- But the variance was enormous. Some jobs made 35% margin. Some made 4%. Two lost money.
- The pattern wasn't random. Jobs with tiled splashbacks consistently ran over. Jobs where the client supplied their own appliances consistently had more back-and-forth.
He didn't need to overhaul his pricing. He needed two adjustments: a standard uplift for tiled splashbacks and a clause about appliance specs being confirmed before install.
Took an afternoon to figure out. Saved thousands over the following year.
How to find your own pattern
You don't need a fancy system. You need a simple feedback loop.
Start logging three things for every job: what you quoted, what you actually spent (materials, hours, any external costs), and one line on what surprised you.
Do this for twenty jobs. Not forever. Just twenty.
Then sort them. Which ones made money? Which ones didn't? Is there a pattern? A certain type of client, a certain type of scope, a certain add-on that always takes longer than you think?
You're not building a pricing calculator. You're training your gut with real data.
The fix is small but it needs to happen
The goal isn't to quote every job to three decimal places. That's not how small operations work, and that's fine.
The goal is to stop letting invisible losses accumulate. To catch the slow margin erosion before it eats your profit. To know which jobs actually make you money and which ones you're doing because they feel busy.
Sometimes it's a pricing adjustment. Sometimes it's a scope clarification you need to start making upfront. Sometimes it's a type of work you should quietly stop offering.
But you can't make any of those calls if the estimate stays in your head and the real numbers never get written down.
If you've got a suspicion that some of your jobs are healthier than others — but no clear way to see it — that's exactly the kind of thing we dig into. Happy to take a look together.