Margin by Service Line: Why 'We Had a Good Month' Is Not an Answer
I worked with a service company a while back that was booked out weeks in advance. Crews running nonstop. Every conversation with the owner started with some version of "we're slammed," said with the kind of pride that comes from turning work away.
Then we sat down to figure out what they were actually making per job.
Nobody could tell me. Not for lack of data. The information existed, it had just never been organized to answer that question. Transactions got categorized into broad buckets that made the P&L balance, and nothing tied a specific cost back to a specific type of work. Materials for a big project and materials for a small one landed in the same account. Labor never got split by job category at all.
The books were fine. The tax return would have been fine. And the owner still could not tell me which half of his business was carrying the other half.
Accurate is not the same as informative.
The questions I ask before I open anything
When an owner tells me they're busy but the money isn't showing up, I want to know a few things before I look at a single report.
What are the different kinds of work you sell? Not the marketing version, the operational version. Which of those do you sell the most of? Which one do you like selling the most? Those are usually different answers, and the gap between them is often where the problem lives. And who touches a job from start to finish, because that tells me where the labor cost actually goes.
Ten minutes of that saves me hours in the file.
Then the balance sheet, even here
I know margin sounds like a P&L question. I still start on the balance sheet, because that's where costs go to hide.
I'm looking for work sitting in inventory or work in progress that should have been costed to a job already. Unbilled work that's been delivered but never invoiced. Equipment purchases that got expensed in one lump instead of being tied to the jobs that used it. Any of those will distort what a service line looks like, and none of them show up on the P&L in a way you'd notice.
If the balance sheet is clean, then the P&L is worth reading. If it isn't, I'm reading fiction.
Revenue and margin are two different questions
Revenue is what you charged. Margin is what's left after the real cost of delivering the work: materials, labor, subcontractors, the equipment tied up in it, everything that had to happen for that job to get done.
A service can post great revenue and terrible margin at the same time, and from the top line you would never see it. That's the trap. Revenue growth feels like winning, and it can be covering for a service line that loses money on every single sale.
Run the numbers on almost any multi-service business and there's usually one offering that customers love, that sells constantly, and that loses a little money every time it goes out the door. It survives because nobody has ever isolated it. Buried in the average, it looks fine.
Why "sell more" makes it worse
Here's the part that catches owners off guard.
When a month comes in soft, the instinct is to push harder on whatever's easiest to sell, which is usually the popular thing. If the popular thing is the one quietly losing money, pushing it doesn't fix anything. It speeds the problem up. You can work your way into a worse month by getting busier, and from the outside it looks like the opposite is happening.
That's why "we're slammed" and "we're barely breaking even" turn up in the same conversation more often than you'd think. Slammed measures activity. Breaking even measures money. A business can max out the first and still fail the second.
Busy and profitable are two different questions. Your books should be able to answer both.
What it takes to actually find out
This is a structure problem, not a data problem. You're already generating everything you need.
It starts with class tracking or job costing set up in QuickBooks so that revenue and its direct costs get tagged to the same service category instead of landing in one undifferentiated pool. Materials, labor, subcontractor costs, anything specific to that job. Once that's in place your P&L stops being a single number and starts being a set of answers. What did this service line bring in. What did it cost to deliver. What's left.
The setup is a one-time lift. The payoff compounds every month after, because it's the difference between guessing which service to grow and knowing.
I'll be straight with you about the cost, though. Doing this properly means going back and recategorizing history, or accepting that your comparisons start from today. Neither is free. It's still worth it, because the alternative is running a business on a number that can't tell you where the money went.
Check your own file this week
- List every distinct kind of work you sell. If the list is longer than you expected, that's already useful.
- Open your chart of accounts. Can you tell which costs belong to which kind of work, or does everything land in one materials account and one labor account?
- Check work in progress and inventory on your balance sheet. Is there cost sitting there that belongs on a job?
- Pick your most popular service. Add up what it cost you to deliver it last month, honestly, including labor. Compare that to what you charged.
If item four comes out closer than you're comfortable with, you've found the thing worth fixing.
Want a second set of eyes on it?
Most owners I talk to have a hunch about which service line is dragging. Usually the hunch is right and the number is worse than they guessed.
A 15-minute call is enough for me to tell you whether your books can answer the question you're asking of them, and roughly what it would take to get them there.