Enter revenue, cost of goods sold and operating expenses. You get operating profit, operating margin, how much of the cost base is advertising, and the revenue you would need to break even.
Gross margin tells you what a sale is worth. Operating margin tells you whether the business that made the sale is worth running. It is the first line in the accounts where the rent, the salaries and the ad budget all have to fit inside the same number.
Operating expenses are the costs of being open, not the costs of selling one more unit. Rent, salaries, software subscriptions, accountancy, insurance, and in almost every case the entire advertising budget.
Advertising is the item people get wrong. It feels variable, because you can switch it off tomorrow, and it scales with ambition rather than with volume. But it does not attach to a unit the way freight does. Spending nothing this month does not change what a sold unit costs you. That makes it an operating expense, and it belongs below gross profit, not inside cost of goods sold.
Owner salary. If you pay yourself, it is an operating expense. If you do not, the margin you are reporting is subsidised by unpaid labour and will collapse the moment you hire a replacement. Put a market salary in even when no money moves.
Depreciation and amortisation. Standard operating margin includes both, which is why it sits below EBITDA rather than beside it. If you strip them out to make the number look better, call the result EBITDA margin and say so.
Interest and tax. Neither belongs here. Operating margin is deliberately blind to how the business is financed, so that two companies with different debt loads can still be compared on how well they trade.
The test is the mirror image of the one for cost of goods sold. Ask whether the cost would still exist if you sold one fewer unit this month. If the answer is yes, it is an operating expense.
| Business shape | Typical gross margin | Typical operating margin |
|---|---|---|
| Established software | 75 to 85% | 15 to 30% |
| Software still growing hard | 75 to 85% | Often negative |
| Branded consumer goods | 50 to 65% | 8 to 15% |
| Ecommerce reseller | 25 to 40% | 2 to 8% |
| Grocery retail | 20 to 28% | 1 to 3% |
| Agency and services | 40 to 60% | 10 to 20% |
The useful reading is the gap between the two columns. A software business converts 80 percent gross into 20 percent operating and loses sixty points to salaries and acquisition. A grocer converts 24 into 2 and loses twenty two points to rent, staff and logistics. The gap is the cost of the machine that produces the sales, and it is far more stable within a category than the margin itself.
Take the worked example on this page. Revenue of $37,410 against $21,698 of goods leaves $15,712 of gross profit, a 42 percent gross margin. Operating expenses of $12,850, of which $10,000 is advertising, leave $2,862 of operating profit. That is a 7.7 percent operating margin.
Now the part that matters. Advertising is 78 percent of every operating expense in that month. Raising spend by $2,900 with no lift in revenue takes the operating margin to zero. The business does not have a gradual decline into loss available to it; it has about four weeks of headroom.
This is why gross margin is the wrong number to budget against. Gross margin says there is $15,712 to play with. Operating margin says $12,850 of it is already committed, and only $2,862 is genuinely yours.
Gross margin is what a sale is worth. Operating margin is whether the business that made it is worth running.
Operating margin is a ratio, and ratios improve for two entirely different reasons. One is that the business got better. The other is that revenue went up while a fixed cost stood still, which is arithmetic rather than achievement. Both look identical on a chart.
The distinction matters when the direction reverses. Operating leverage runs in both directions with equal force. A business that gained four points of margin on a 30 percent revenue increase will give back more than four when revenue falls 30 percent, because some of those fixed costs turn out to have been growing quietly all along.
The second trap is comparison. Operating margin is only comparable between businesses that draw the line between cost of goods and operating expenses in the same place. A competitor reporting 14 percent against your 8 may simply be classifying fulfilment labour above the line where you put it below. Before concluding you are being beaten, check that you are both counting the same way.
Compute it from the accounts you actually file, quarterly, and watch the trend rather than the level.
No. Operating margin is calculated after depreciation and amortisation; EBITDA margin adds both back. For an asset-light business the two are close. For anything holding equipment, vehicles or capitalised software the gap is wide, and quoting EBITDA margin while calling it operating margin flatters the result.
Below gross profit, as an operating expense. It does not attach to a unit sold, so putting it in cost of goods sold understates gross margin and makes break-even ROAS look worse than it is. Keeping it in operating expenses is also what lets you see it as a share of the cost base, which is the number that usually decides how much spend the business can survive.
It depends almost entirely on the shape of the business. Grocery retail runs on one to three percent and is healthy; software running on three percent is not. The useful question is not the level but the direction, and whether the gap between gross margin and operating margin is widening for a reason you chose.
It can, and for a company deliberately buying growth it often is. What separates the two cases is whether the loss is caused by a cost that scales down on command, such as advertising, or by a cost base that has hardened into rent and salaries. The first is a decision. The second is a problem.