Your Truck Makes $87/Hour. Your Office Makes –$12.
Why Don't You Know This?

Ask most contractors which of their trucks makes the most money and they'll answer without hesitation: the busy one. The truck that's booked solid, running calls dawn to dark, the one they'd buy two more of if they could find the techs. It feels obvious. It's also, often, dead wrong.

Here's the uncomfortable truth: your average productive field hour probably throws off something like $87 in margin — and every hour your doors are open, the office quietly eats about $12 of it back. But that $87 is a blend, and the blend hides everything that matters. One truck might be making $112 an hour. Another, the one you swear is your workhorse, might be making $41. Same company, same logo on the door, nearly 3x difference in what they actually contribute. Most owners have no idea — because nobody ever taught them to look at the business one unit at a time.

This is unit economics, and it's the single most useful lens a trades business can adopt. It's not accounting theory — it's the difference between growing the truck that's quietly bleeding you and growing the one that's carrying the company. Let's break it down, with real numbers.

By Carrie Anderson — Co-Founder, 406 Consulting Group. Commercial banking and underwriting background — 300+ loan reviews — where the whole job was figuring out which businesses actually made money, and where.

Let's make this concrete. Meet Bridger Mechanical, a plumbing and heating shop in Bozeman doing about $2M a year across three trucks. The owner, we'll call him Ryan, would tell you Truck 1 is the star. Dave runs it — emergency service calls, forty-five billable hours a week, always slammed. Truck 2 is the install crew doing system replacements; they run maybe thirty billable hours a week and Ryan half-jokes they're "taking their time."

If you asked Ryan at the bar which truck he'd clone, he'd say Truck 1 every time. More hours, more tickets, more revenue. It's the obvious answer, and it's the one almost every contractor gives. But "busy" and "profitable" are not the same word — and when we actually ran the numbers on Bridger, the busy truck and the slow truck traded places.

To see why, you have to stop looking at the company as one big number and start looking at it one truck at a time. That's the whole game.

"We did two million this year." It feels great to say. It tells you almost nothing about whether you made money — and even less about where. Revenue is the number contractors brag about and bankers glance past, because a business can grow revenue every year and slowly go broke doing it. Two contractors can both hit $2M: one takes home $250K, the other takes home $40K and can't figure out why. The difference isn't how much they sold. It's the margin underneath each thing they sold.

For trades especially, revenue hides a brutal amount of variation. An emergency service call and a full system replacement both show up as "revenue," but one might carry a 12% margin after everything and the other 35%. Chase revenue and you'll happily fill your schedule with the 12% work because it keeps everyone busy — and wonder every December why busy didn't turn into money.

Revenue is the top of the funnel. Unit economics is what happens at the bottom — and the bottom is the only part that pays you.

"Unit economics" sounds like something a tech startup says. Strip the jargon and it's dead simple: pick the thing your business repeats, and figure out what one of them actually makes you. For a contractor, the "unit" is usually one of these:

You don't need all of these at once. Start with one — for most trades, per truck or per field hour is the fastest gut-punch of clarity. The point is to stop asking "did we make money?" and start asking "which of these made money, and how much?"

Here's the one number to burn into your brain: contribution margin per field hour. It's the revenue a unit brings in, minus the costs that unit actually causes — labor, materials, fuel, truck wear, callbacks — divided by the productive hours it worked. It's not net profit (overhead comes later); it's what each unit contributes toward covering the office and paying you. Back to Bridger's two trucks:

Look at that. Truck 1 bills less per hour, burns more parts on small jobs, drives an old van, and eats callbacks from a rushed junior tech — so it nets about $41 an hour. Truck 2 does bigger, cleaner replacement jobs with a better attach rate and a newer van — about $112 an hour. The "slow" truck contributes almost three times as much for every hour it works. Ryan had it exactly backwards.

The reason most contractors think Truck 1 is the winner is that they only count the obvious cost — what they pay the tech — and skip the rest. To get an honest number, you have to load in the costs each unit really causes:

None of this is exotic. It's just the stuff that never makes it onto the invoice, so it never makes it into the owner's mental math — and it's exactly where the busy truck quietly loses the race.

There's one more unit nobody thinks of as a unit: the office. Rent, the dispatcher, software, insurance, the bookkeeper, and — usually — the owner doing quotes and returning calls at 9pm. None of it touches a wrench, but all of it has to be paid, and the only place the money comes from is the field. Spread that overhead across the hours your trucks actually bill, and it lands somewhere around $12 per field hour at a shop like Bridger.

That's not a criticism of overhead — you need an office. It's a benchmark. It means every field hour has to clear $12 just to break even on the building before it contributes a dime to you. Truck 2 at $112 clears it easily. Truck 1 at $41 still clears it — but there's a lot less left, and if its margin slips even a little, it's working to keep the lights on and nothing more. The office is the hurdle every truck has to jump; unit economics tells you which trucks are barely clearing it.

Knowing your office costs $12 an hour also keeps you honest about growth: adding overhead (a second dispatcher, a bigger shop) raises the hurdle for every truck. Worth it if it lets your good trucks run more billable hours; a quiet killer if it just raises the bar the weak ones already struggle to clear.

Once you run the numbers per unit, the same handful of surprises show up in almost every trades business:

None of these are visible in a company-wide P&L. They only appear when you split the business into units and look at each one's margin. That's the whole reason to do this.

Seeing the numbers is useless if you don't act on them. The good news: unit economics points straight at the decision. For any weak unit, you've got four honest options — and "fire the people" usually isn't one of them.

For Ryan, the answer wasn't firing Dave — it was retraining him, moving Truck 1 upmarket toward replacements, raising the service-call minimum, and putting the next new hire on the install side that was actually making money. Same three trucks, a very different bottom line a year later.

Here's the part where most owners check out: "great idea, but I'm not doing a research project every month." Fair. The trick is that you don't calculate unit economics by hand — you build it into the books once, and then it just falls out every month. That means setting up your accounting to tag revenue and direct costs by unit: class or location tracking for each truck or crew, job costing that captures labor and materials by job, and a clean split between direct costs and overhead.

This is exactly why we argue that accounting should be designed around how the business actually runs, not just around filing a tax return. A generic chart of accounts gives you one company-wide P&L and hides every insight in this article. A system built for a trades business gives you margin per truck, per job type, and per hour — automatically, every month — so the answer to "which truck should I clone?" stops being a bar argument and starts being a number.

A couple of our tools get you started fast: the Cost-Per-Mile calculator nails the true cost of running a truck, and the Break-Even Calculator shows the revenue each unit has to clear. Building the ongoing system is what our business systems and bookkeeping work is for.

The instinct is that this is big-company stuff — that you need a controller and a fancy system to think this way. You don't. A three-truck shop can run unit economics on a well-built QuickBooks file and a simple monthly review. What you need isn't scale; it's the setup and someone to read the numbers with you a few times until it clicks.

That's the whole idea behind fractional financial help: you get the controller-and-CFO thinking — margin per unit, pricing, where to grow — without a six-figure hire, and you get it remotely. Most of our own clients never set foot in our office; the work runs on shared screens and clean cloud books. A contractor doing $800K can absolutely have this. In fact, that's exactly the size where knowing which truck makes money is the difference between the next hire growing your profit and quietly shrinking it.

If you're not sure where you stand, our Financial Maturity Assessment is a fast read on what your numbers can and can't yet tell you.

You can't manage what you refuse to measure — and "we did two million" isn't a measurement, it's a headline. The contractors who pull away from the pack aren't the ones with the most trucks or the busiest schedule. They're the ones who know, to the dollar, what each truck, crew, and job type contributes — and who point their growth at the winners instead of the noise.

You don't have to boil the ocean. Start with one unit. Pick your busiest truck, load in the real costs, and figure out what it makes per billable hour. Then do the one you think is slow. If they trade places — and they often do — you've just found the most valuable number in your business. And it was hiding in plain sight the whole time.

The related read: the true cost of letting an amateur run your books — because none of this shows up if the numbers underneath aren't clean.

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