Your operating margin compares operating profit as a percentage of sales. Operating profit is your gross profit minus selling and administrative expenses such as rent, depreciation, salaries, marketing and utilities.
Continuing with our previous example, if your business has sales and administrative costs of $5,000 and $50,000 in sales, then its operating profit margin ratio is 100 x ($5,000 / $50,000), or 10%.
Analyzing your gross margin and operating margin together can tell you how well you’re managing operating expenses. For example, if your gross margin is high but your operating margin is low relative to industry benchmarks, then your operational costs maybe too high and you should consider ways to decrease fixed expenses.
Net profit margin ratio
Your net margin on the other hand, measures net profit—or your bottom line— as a percentage of sales. Net profit is your operating profit minus interest and tax. Again, following our example, if your interest and tax expenses add up to $1,000, then your net margin ratio is 100 x ($4,000 / $50,000), or 8%.
A strong net margin is an indicator of good management of overall expenses. A weak margin could signal potential problems with future debt repayments for businesses that are highly leveraged.
If you have a good operating profit margin but a slim net margin it is likely that a post-sales expense is to blame. This could include taxes or interest rates. That might be a sign to look at refinancing in an effort to lower your interest rates, or review how your tax structure is set up.