Parts or Labor: Which Side of Your Auto Repair Shop Makes the Money?
An auto repair shop is really two businesses sharing one building.
One sells parts. The other sells time. They have different costs, different margins, and different problems. Most shops track them as one number.
That's where the confusion starts.
One deposit, two different businesses
At the end of the week the money comes in as one pile. A customer pays one invoice. That invoice had a water pump on it and 3 hours of labor. The card processor deposits one amount.
So the books show revenue. They don't show which half earned it.
You can run a shop that way for years. Plenty do. The trouble shows up when something shifts and you can't tell what moved.
The questions that get hard to answer
Did my margin drop because parts cost more, or because jobs are running longer than I quoted?
Am I making money on diagnostic time, or am I giving it away?
Gross sales went up. Why didn't the bank balance?
Every one of those has an answer. You just can't get to it from a single revenue line. It's the same problem contractors run into when they can't tell which construction jobs made a profit.
Why this hits harder in Montana
Parts don't just cost more here. They take longer to get here.
A shop in Bozeman or Belgrade waiting on a part from a warehouse two states away has a car on the lift, a bay tied up, and a customer calling. Some shops eat the freight. Some mark it up. Most don't track it either way.
Then there's the season. Winter brings batteries, tires, and no-start calls. Spring brings suspension work from the roads. Summer brings travelers who break down on the way through the valley and need it fixed today. The mix of parts work and labor work moves all year. If the books don't split it, you never see the shift.
Montana also has no general state sales tax, which means shops here skip a layer of parts-sales recordkeeping that shops in other states deal with. That's a break. It also means nobody ever built the habit of tracking parts separately, because no state form forced it.
What splitting it out shows you
When parts and labor sit in their own accounts, a few things get clear fast.
You see your real labor rate. Not the one printed on the wall. What you actually collected per hour after comebacks, warranty work, and the jobs that ran long.
You see whether your parts markup is holding. Supplier prices move. Your markup usually doesn't move with them unless somebody is watching.
You see which work is worth chasing. A fleet account that's mostly labor and a retail customer who's mostly parts are not the same customer, even if they spend the same.
None of that takes new software. It takes setting the accounts up right once and staying consistent after that.
Where to start
Pull your last 3 months and try to answer one question. How much of that was parts, and how much was labor?
If you can answer it, you're ahead of most shops.
If you can't, that's the thing to fix first. It's a setup problem, and you only have to solve it once. If you're not sure who handles that, we wrote about the difference between a bookkeeper and an accountant and which one a small business actually needs.
Blackfin does bookkeeping and tax for service businesses around Bozeman and the Gallatin Valley. Both sit under one roof, so whoever cleans up your parts and labor accounts is the same person looking at them again at year end. When you call or email, you hear back the same day.
If you want to know which half of your shop is carrying the other, give us a call at 406-404-8955.