You Know Your Revenue. Do You Know Which Service Actually Makes Money?

Your profit and loss statement answers one question: did the business make money this month? It can’t answer the one you actually think about in the truck, or the chair, or the car on the way home: which of the things we sell is making the money, and which one is quietly eating it?

A landscaper with maintenance, installs, and snow. A dental practice with hygiene, restorative, and cosmetic. An agency with retainers, projects, and hosting. A contractor with service calls and new construction. Every one of them has a service the owner is sure is the profitable one. We run an accounting firm, and about half the time, when we build the report, they’re wrong.

What the report is

It’s called contribution margin by service line, and it’s simpler than it sounds. For each thing you sell, take its revenue and subtract only the costs that exist because you sell it: the labor that did the work, the materials, the subcontractors, the software only that service uses. What’s left is what that service contributes toward your rent, your admin staff, and your profit.

Rent and overhead are not divided up between services. Every formula for doing that produces an argument instead of a decision. The decisions are all in the contribution line.

What it takes to build

Three things, set up once, and then it comes out of your monthly books automatically:

1. Every invoice line tagged with its service. Your accountant maps your products and services to three or four lines, so the tag happens when the invoice is created and nobody has to remember.
2. Labor split between services. If your people are dedicated to one service, this is automatic from payroll. If they split, it comes from time tracking, your scheduling system, or, honestly, a written estimate from you that gets applied every month until you revise it. A consistent estimate beats a precise number nobody produces.
3. Direct costs tagged at the bill. Materials, subs, and service-specific software get tagged when the bill is entered. The same rules that categorize the expense assign the service.

Once that’s in place, the report runs off the closed month. No spreadsheet, no annual project.

The three things it almost always shows

• The service you started with loses money. Priced years ago, done by your most expensive people, never repriced because it’s “our bread and butter.” The report shows it’s the bread and someone else’s butter.
• The boring service carries the company. The maintenance contracts, the hygiene schedule, the hosting. Highest margin, least attention.
• Labor is the whole story. In a service business, materials rarely decide margin. Who does the work does. A job done by you and the senior tech has a different margin than the same job done by the newest hire, and you’ve never seen that number side by side.

What a CFO does with it

The report is a chart. The value is the conversation. A fractional CFO walks in and says: this line runs at 9% contribution, the other two at 35% and 41%, and here are your three choices. Raise the price on the low line enough to bring it to 25%. Change who does that work. Or keep it as a loss leader on purpose, with the cost written down, because it feeds the other two.

Then the math, in dollars. If the low-margin line is 30% of your revenue, a 12% price increase on it, after the customers you’d expect to lose, is a specific number added to annual profit. Owners don’t act on percentages. They act on “this is worth $48,000 a year and it takes one email to your customers.” That one meeting usually pays for the year of advisory.

Why now

Price changes take effect at renewal or at the new year. A report built in October gives you November to decide and December to communicate. Built in February, you’ve already locked in another year of the wrong price.

Where we come in

We set up the three pieces once, run the report as part of your monthly close, and sit down with you each quarter to turn it into a decision. It’s an add-on to bookkeeping, not a separate project, and the first quarterly meeting is usually the one where a price finally changes. If you’ve never seen your margin by service, reach out or read more about our advisory work. We’ll tell you which service is paying for the others.