Job Costing for Contractors: How to Find Out Which Jobs Actually Make Money

You wrapped three jobs last quarter: a $12,000 bathroom, an $18,000 deck, and a $45,000 kitchen. There’s more money in the account than when you started, so the quarter went fine. If someone asked which job made you the most money, you’d probably say the kitchen. It had the biggest price tag.

You might be wrong. The biggest job and the most profitable job aren’t always the same one. After two extra weeks of labor and a subcontractor who came back twice, the kitchen may have barely broken even, while the deck and the bathroom carried the quarter. Without job costing, there’s no way to know.

Margins don’t leave much room for guessing. In NAHB’s latest Remodelers’ Cost of Doing Business Study, the average remodeler earned a 29.9% gross profit margin in 2024 but a net margin of just 6.3% after operating costs. At that level, one job that runs over can erase the profit from several that went well.

Dominique Gabriel of Designs by D&J says the business side of remodeling takes its own set of skills. “A lot of contractors start because they love the trade. You might love welding, painting, carpentry, or construction, but performing the work and operating a profitable business are two different things,” she says. “Job costing gives you the data to understand which projects are actually making money and which ones aren’t. Once you understand that, you can operate very differently.”

What job costing is, and when it starts to matter

Job costing means tracking every dollar you spend on a project against what you charged for it, one job at a time. Most contractors don’t start there. Early on, Gabriel says, the excitement of winning a job comes first, and the budget gets figured out along the way.

That works when there’s one job to watch. It stops working as your schedule fills up. “It’s not about the project size. More often than not, it’s about the number of projects that you have, and that’s when job costing becomes extremely important,” Gabriel says. “It’s one thing to manage one project independently. It’s another thing to manage five and ten and fifteen projects concurrently.”

Track four direct costs on every job

Direct costs are everything you spend because of a specific job. Set up a category for each one, and log every expense to the job it belongs to.

1. Labor: Hours worked on the job multiplied by what each worker costs you, including payroll taxes and benefits. Our guide to contractor time tracking covers how to capture those hours accurately.
2. Materials: Everything purchased for the job, minus returns.
3. Subcontractors: Every invoice from trade partners, including return visits. For the average remodeler, trade contractor costs ran about 30% of revenue in 2024, according to NAHB.
4. Other job costs: Permits, dumpsters, equipment rentals, and anything else you wouldn’t have spent without this project.

Labor needs the closest watch. Gabriel says most contractors know their hourly labor rates well, since they work with them every day. The risk is the schedule. “If a contractor is not accurately managing their schedule, the project could potentially run over,” she says. “And that’s where you’re now under budget for what you’ve allotted for labor.”

Give every job its share of overhead

Overhead is what it costs to run the business whether or not a job is happening: insurance, trucks, the office, software, and your own salary. It adds up. We mentioned earlier that NAHB found remodelers averaged a 29.9% gross margin and a 6.3% net margin. Put together, out of every dollar the average remodeler brought in, about 70 cents went to job costs, about 24 cents went to overhead, and about 6 cents was profit. A job that covers its direct costs but not its share of overhead loses money.

Gabriel describes two ways to assign it. Here’s how each works for a contractor with $120,000 in yearly overhead, $800,000 in revenue, and about 12 jobs a year.

The hard-dollar method. “You can apply a hard dollar cost divided across all of the projects that you typically take on,” Gabriel says. “If you know that you can operate on one to two projects per quarter, great. That sets the tone.” In the example, that assigns $10,000 to every job.

The percentage method. This option works better “because not every project is the same,” she says. With overhead at 15% of revenue, a $40,000 kitchen carries $6,000 and a $10,000 bathroom carries $1,500. If your job sizes vary a lot, this is usually the better fit.

Your move: Add up last year’s overhead, choose a method, and add overhead as its own line in every estimate you write this month.

Compare estimated and actual costs while the job is running

Job costing pays off most when it catches problems before the final invoice. That matters more when prices are moving. Residential building material prices were up 5% from a year earlier in July 2026, and softwood lumber was up 17.3%. An estimate written in the spring may not match what the supply house charges in the fall.

Gabriel’s firm runs its job costing through QuickBooks alongside a work-in-progress schedule, and she keeps the tracking itself simple, often in a spreadsheet. “You always want to have checks and balances,” she says. A basic work-in-progress schedule tracks four things for each active job:

• Budget: The estimated cost for each of the four direct cost categories.
• Costs to date: What you’ve actually spent so far in each category.
• Percent complete: How far along the work is.
• Warning signs: Any category where spending is running ahead of progress, like 70% of the labor budget spent on a job that’s only 50% done.

Update each open job’s actual costs against its estimate once a week, category by category. When materials or labor start running ahead of the estimate, you can adjust the schedule, talk to the homeowner about a change order, or at least learn why before the next bid.

What to do: After every completed job, write down the estimated and actual cost for each of the four categories. After a few months, those notes become your best estimating tool.

Use your numbers to price and explain your work

Once you have a few months of data, sort completed jobs by type and compare margins. One type may consistently earn more than the others, which tells you where to focus. Another may need a higher price.

Clear numbers also make pricing easier to explain. Gabriel says homeowners often don’t understand what goes into labor costs, and she sees explaining it as part of the job. “If you’re looking to do business with the public and stay in business, you have to be open, transparent, and you have to communicate,” she says. “I feel like I’m not successful if they don’t understand the labor costs or the man-hours or even the materials going into the project, because they should feel comfortable and confident that they’ve invested with the right partner.”

Cost is a real hurdle for homeowners. 43% of homeowners who bought during the low-rate years delayed or canceled a renovation in the past year over cost or financing concerns, according to Acorn Finance’s Stay-and-Renovate report. A transparent estimate helps, and so does a smaller number. Offering financing through Acorn Finance lets homeowners compare loan offers and see the project as a more manageable monthly payment.

Run the back office like the second business it is

Job costing lives in the back office, which Gabriel sees as a business of its own. “Understand that in construction, you are operating two businesses at the same time. One is going to be your back-office administration and two is going to be your construction, your field crew,” she says. “Those are two separate companies that run concurrently, and you have to be, as the CEO, the person that allows them to run together.”

Getting the numbers right is what lets both sides work. Cleaner estimates lead to better budgets and tighter financial controls, which is what lets a crew repeat good work job after job. “Once you get a better handle on your estimation, that is going to be the foundation for success for the projects to come,” Gabriel says.

Your job costing action plan

This week: Pull the receipts, invoices, and timesheets for your last three completed jobs. Compare each job’s total cost to what you charged.

This month: Set up the four direct cost categories for every open job, calculate an overhead rate from last year’s numbers, and add it to every new estimate.

This quarter: Update actual costs weekly, compare margins by job type, and adjust pricing on the type that earns the least.

The bottom line

Job costing turns a hunch about which jobs make money into a number you can act on. Track direct costs, give every job its share of overhead, and compare estimates to actuals while there’s still time to adjust. A few months of that, and your estimates, your pricing, and your choice of jobs all get sharper.

Know what every job costs. Then make the price easier to say yes to. Acorn Finance lets your customers compare loan offers in minutes, turning a $25,000 remodel into a monthly payment of about $400. See how you can offer financing through Acorn Finance.