How to Calculate Profit Margin: Formulas, Examples, and Benchmarks

3. Net profit margin

(Revenue − All costs) ÷ Revenue

Everything comes out: interest on debt, taxes, depreciation, one-time costs. Net margin is what a lender underwrites, what a buyer values, and what the IRS taxes. It is also the number owners quote least accurately, because most of them have never seen it calculated on properly reconciled books.

A worked example

A contractor bills $50,000 in March. Materials and subcontractors run $22,000. Overhead is $15,000. Interest and other costs are $2,000.

Revenue	$50,000
Less cost of goods sold	($22,000)
Gross profit	$28,000	56.0% gross margin
Less operating expenses	($15,000)
Operating profit	$13,000	26.0% operating margin
Less interest and other	($2,000)
Net profit	$11,000	22.0% net margin

Three margins, one month, one business: 56%, 26%, 22%. When someone tells you their margin is "about 50%," they are almost always quoting gross and thinking about net.

Margin vs. markup: the expensive mistake

Margin divides profit by the price. Markup divides the same profit by the cost.

An item costs $100 and sells for $150. Profit is $50.

• Margin = $50 ÷ $150 = 33.3%
• Markup = $50 ÷ $100 = 50%

Same transaction, two numbers seventeen points apart. Here is where it costs real money: an owner decides they need a 30% margin, so they add 30% to cost. That produces a 23.1% margin, not 30%. Across a year of jobs, that gap is often the entire difference between a profitable year and a break-even one.

To price for a target margin, divide cost by (1 − margin):

Target margin	Required markup	Price on $100 cost
10%	11.1%	$111
20%	25.0%	$125
30%	42.9%	$143
40%	66.7%	$167
50%	100.0%	$200

What is a good profit margin?

The honest answer is that it depends on your model far more than on your management. Rules of thumb we find useful when reviewing a new client's books:

• Professional services: gross 70–90%, net 15–25%. Direct cost is labor, so utilization drives everything.
• Trades and construction: gross 20–35%, net 5–12%. Job-level costing matters more than the company total.
• Retail and e-commerce: gross 30–50%, net 2–8%. Shipping, returns, and ad spend move net more than pricing does.
• Restaurants: gross 60–70%, net 3–9%. Food cost sets gross; labor and rent set net.
• Medical and dental: gross 55–75%, net 10–20%. Contractual write-offs must be recorded separately from collections.

These are working ranges from the books we see, not results of a formal survey. The more useful comparison is against yourself: is your net margin stable or improving over the last six months, and does it cover debt service with room left?

Three reasons your margin is wrong

Direct costs are buried in overhead

If subcontractor payments, materials, or merchant fees are coded to general expenses instead of COGS, your gross margin is overstated and you cannot tell whether pricing works. This is the single most common chart-of-accounts problem we fix in a cleanup.

The owner works for free

A margin calculated without paying yourself a market wage for the work you actually do is not a margin. If you are the technician and the salesperson, your P&L should carry the cost of replacing you. Otherwise you are subsidizing the business and calling it profit.

Loan principal is treated as an expense

Principal repayment reduces cash and a liability, but never touches the P&L. Only interest does. Owners who subtract the whole loan payment from profit understate margin; owners who ignore debt service entirely overestimate how much more they can borrow.

Margin is not cash

You can post a 20% net margin and still not make payroll. Margin is an accrual measure; cash is a timing measure. The gap comes from unpaid invoices, inventory bought ahead of sales, loan principal, and owner draws.

That gap is the most common reason a profitable business fails, which is why we pair every margin review with a forecast. Our cash flow calculator and 13-week forecast handle that side.

Do the math on your own numbers

Open the profit margin calculator, enter one month of revenue and costs, and you will get all three margins plus the revenue required to hit a target. If the result looks implausible for your industry, the problem is usually the books rather than the business — and that is fixable. Tell us where your books stand and we will tell you what it takes to get a margin you can trust.