A trade business can have a record revenue year and finish it with less money than it started. When that happens, the usual cause is that prices covered the jobs but not the business around them. Net profit is the number that catches this, because it is what remains after the office, the trucks, the phones, the insurance and the owner have all been paid.
Net profit in plain English
Picture the profit and loss statement as a staircase going down.
| Step | Example (made-up shop) |
|---|---|
| Revenue | $2,000,000 |
| minus direct job costs (burdened field labor, parts, equipment, subs) | −$1,100,000 |
| = Gross profit (45% gross margin) | $900,000 |
| minus overhead (office staff, rent, insurance, software, marketing, non-job vehicles) | −$560,000 |
| minus owner's market-rate salary | −$140,000 |
| minus interest and depreciation | −$20,000 |
| = Net profit before tax (9% net margin) | $180,000 |
Gross profit is how much each job contributed. Net profit is what the whole business kept. The gap between them is overhead, and overhead does not shrink when the phones go quiet in a shoulder season.
How do you calculate net profit margin?
Metric
Net profit margin %
The share of each revenue dollar the business keeps after every cost, including a fair salary for the owner.
(Revenue − direct costs − overhead − owner salary − interest) ÷ revenue × 100
Where the numbers come from: Your monthly profit and loss statement, with the owner's pay recorded as a cost rather than a draw.
IRS Publication 334 describes net profit the same way for tax purposes: you figure it "by subtracting business expenses from business income."1 The differences between tax net profit and management net profit usually come down to two items: how the owner is paid, and timing differences such as depreciation.
The owner's pay problem
A sole proprietor's tax return can't include the owner's salary as an expense. The IRS says plainly: "You can't deduct your own salary or any personal withdrawals you make from your business."1 That makes the tax return's net profit a mix of the owner's wages and the business's real profit.
S corporations work the other way. The IRS says an S corporation must pay a shareholder-employee reasonable compensation for their services before taking non-wage distributions.2
For running the business, treat both the same way: record a market-rate salary for the work the owner actually does, whether that's running a truck, selling or managing. If you'd have to hire a general manager at $140,000 to replace yourself, that's the number. Profit that only exists because the owner works for free is not profit the business can sell or rely on.
Gross margin vs net profit
| Gross margin | Net profit margin | |
|---|---|---|
| What it subtracts | Only the direct cost of each job | Every cost, including overhead and the owner's salary |
| What it answers | Are my prices right for the work? | Is the business making money overall? |
| How fast it moves | Job by job, visible within days | Month by month, after the books close |
| Where you see it | Job costing, price book | Profit and loss statement |
| Main levers | Pricing, labor efficiency, return trips, discounts | Gross margin, overhead size, revenue volume |
The two are linked by one identity: net margin equals gross margin minus overhead as a share of revenue. With a 45% gross margin and overhead at 36% of revenue, net margin is 9%. That gives you exactly two ways to raise net profit: widen gross margin or shrink overhead's share, and growing revenue only helps if it does the second.
What is a good net profit margin?
There is no reliable public benchmark for residential HVAC, plumbing or electrical net margin, so this page doesn't quote one. Industry figures that circulate online tend to come from vendor or consultant surveys with unclear samples, and they rarely say whether the owner's salary was counted.
What the public data does show is how common the cash squeeze is. In the Federal Reserve Banks' 2024 Small Business Credit Survey of 7,653 employer firms, 75% named rising costs of goods, services or wages as a financial challenge and 56% named paying operating expenses.3
75%
Small employer firms citing rising costs of goods, services or wages as a challenge
Those are all small businesses, not trade contractors specifically. Use your own history as the benchmark: the same month last year, with the owner's salary treated the same way.
What moves net profit?
| Lever | Why it works | How to check |
|---|---|---|
| Overhead built into the labor rate | Every billable hour carries its share of fixed cost | Overhead per billable hour vs what your rate includes |
| Billable hours per tech | Fixed overhead spread over more billed hours | Billable hours ÷ paid hours, by tech |
| Gross margin by job type | Weak job types drag the blend down | Margin per job type, monthly |
| Overhead that scales with revenue | Office headcount and software added "for growth" | Overhead as % of revenue, trailing 12 months |
| Collections | Bad debt is revenue you booked and never got | Write-offs and 90+ day A/R |
A monthly net profit review
- Profit and loss closed within two weeks of month end
- Owner's market-rate salary recorded as a cost
- Same month last year next to this month
- Overhead as a share of revenue, trailing 12 months
- Gross margin by job type for the month
- Any one-time costs called out separately
Where net profit lives in TradesWork
TradesWork doesn't produce a profit and loss statement; net profit belongs in your accounting system, where overhead is recorded. What TradesWork does is keep the inputs honest. Job costing gives you gross margin per job, with burdened labor and missing costs shown as unknown rather than $0. The QuickBooks Online sync posts invoices, payments, refunds and voids every 15 minutes, so the revenue your accountant closes the month on matches the revenue you ran the business on.
For the overhead side of the equation, see overhead recovery. For the weekly numbers that predict next month's profit, the Monday KPI scorecard is a good starting point.
Footnotes
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Internal Revenue Service, Publication 334, Tax Guide for Small Business, chapter 9 (Figuring Net Profit or Loss) and its guidance on the owner's own salary and withdrawals. https://www.irs.gov/publications/p334 ↩ ↩2
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Internal Revenue Service, "S corporation compensation and medical insurance issues." https://www.irs.gov/businesses/small-businesses-self-employed/s-corporation-compensation-and-medical-insurance-issues ↩
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Federal Reserve Banks, Small Business Credit Survey: 2025 Report on Employer Firms (2024 survey, fielded September to November 2024, 7,653 responses). https://fedsmallbusiness.org/-/media/project/clevelandfedtenant/fsbsite/reports/2025/2025-report-on-employer-firms.pdf ↩
