What Is Operating Margin?
Operating margin is operating income expressed as a percentage of revenue: the share of each sales dollar that the core business keeps after both production costs and day-to-day operating expenses, before interest and tax.
Operating margin sits one step deeper than gross margin because it also absorbs research and development, marketing, general administration and depreciation of operating assets. It therefore captures operating leverage: a company whose revenue grows faster than its operating costs will see this margin expand, because each additional sales dollar carries less extra overhead than the average dollar before it.
Because interest and tax are excluded, operating margin is the cleanest efficiency comparison between companies with different borrowing levels or tax homes, and between a company and its own past after its financing has changed. Two firms can post identical net margins for entirely different reasons — one efficient but heavily borrowed, the other less efficient but debt-free — and the operating line is where that difference becomes visible.
Operating margin can be distorted in a single year by items that sit inside operating income: restructuring charges, impairments and litigation costs are common examples. A one-year dip is a question, not a conclusion. The honest test is the multi-year run of the margin alongside the explanation in the filing's management discussion, which is why this site's company pages print operating income and revenue for every reported year side by side.
Putting it into practice
Practise by reconciling the two margins on one company page. Start with gross margin, then subtract each operating expense as a percentage of revenue — research, marketing, administration — using the multi-year table. What remains is the operating margin, and the subtraction exercise shows exactly which cost line is expanding or shrinking the result. Analysts call this a common-size income statement, and building one from filing figures takes minutes once the habit forms.
A worked example from a real filing
Abstract definitions stick better with a real number attached. Take Nvidia Corp (NVDA): in fiscal 2026 it reported revenue of $215.94 billion in its annual 10-K filing, as republished in the SEC EDGAR company facts dataset retrieved in October 2026. Open its company page and you can place that figure next to the same company's net income, operating cash flow, total assets and diluted earnings per share for the same year — the relationships between the measures, not any single one of them, are where understanding lives. Then compare it with peers in the rankings, where the same measures are lined up across the largest filers.
For the full set of plain-English explainers, return to the Learn index, and for exactly how this site selects and labels figures, read the methodology page.