You had a record month. Sales were up, the till kept ringing, and yet the bank balance barely moved. So what went wrong? Often, the answer hides in two small percentages. Once you calculate gross profit margin and net profit margin, you can see where each sale really ends up.
The good news is that the maths is simple. In fact, you only need a few numbers from your sales records and your expense list. Then a calculator, or a spreadsheet, does the rest.
In this guide, you’ll learn how to calculate gross profit margin and net profit margin step by step. We’ll use one worked example from start to finish. Besides that, you’ll see the difference between margin and markup, the mistakes that skew the results, and practical ways to improve both numbers.
Key takeaways
✔ Gross profit margin = (Revenue minus COGS) divided by Revenue, times 100.
✔ Net profit margin = Net profit divided by Revenue, times 100.
✔ Gross margin shows how well you price and produce. Net margin shows what you actually keep.
✔ Margin and markup are not the same thing, so don't mix them up.
✔ Track both percentages every month, then compare them over time.
What Gross Profit Margin and Net Profit Margin Actually Tell You
A profit margin is profit expressed as a percentage of revenue. In other words, it tells you how many cents you keep from every dollar of sales. The margin formula is profit divided by revenue, times 100. Which profit you use decides which margin you get.
Gross profit margin looks at what is left after the direct costs of making or delivering your product or service. These direct costs are called the cost of goods sold, or COGS. For a shop, COGS is mostly the price you paid for stock. Similarly, for a bakery, it is flour, butter and packaging.
Net profit margin goes further. It shows what is left after every expense, including COGS, rent, wages, marketing, interest and tax. Therefore, it gives you the full picture of what the business really earns.
Think of it this way. First, gross margin tells you whether your product makes money. Net margin tells you whether your business does.
What You Need Before You Calculate Gross Profit Margin
Before you start, collect these figures for the same period, such as one month or one quarter:
- Total revenue (sales after returns and discounts)
- Cost of goods sold
- Operating expenses, such as rent, salaries, utilities and marketing
- Interest paid on loans
- Tax charged on your profit
Luckily, most of these sit on your income statement, also called the profit and loss statement. If you’re not sure where to find them, our guide to the income statement shows each line in plain language.
Accurate records matter here, because the IRS recordkeeping guide explains why keeping clean, complete records protects you at tax time. The same records make your margin figures trustworthy.
How to Calculate Gross Profit Margin Step by Step
Here is the formula:
Gross profit margin = (Revenue minus COGS) ÷ Revenue × 100
We’ll use a simple example. So imagine a small café with $50,000 in sales last month. These numbers are for illustration only.
Step 1: Find Revenue Before You Calculate Gross Profit Margin
Start with the money you earned from sales in the period. Use net sales, meaning sales after returns and discounts. Also, if you collect sales tax for the government, leave it out, because that money isn’t yours.
In our example, revenue is $50,000.
Step 2: Add Up Your Cost of Goods Sold
Next, add every direct cost tied to what you sold. For the café, that includes coffee beans, milk, pastries, cups and the kitchen staff who make the food. However, rent for the shop and marketing costs are not COGS, so leave those for later.
Let’s say direct costs came to $20,000. If you’re unsure what counts, see our guide on what COGS includes.
Step 3: Subtract COGS From Revenue to Get Gross Profit
Now subtract, because gross profit is revenue minus COGS.
$50,000 − $20,000 = $30,000 gross profit
Step 4: Calculate Gross Profit Margin as a Percentage
Finally, divide gross profit by revenue and multiply by 100.
$30,000 ÷ $50,000 = 0.60, and 0.60 × 100 = 60%
That means the café keeps 60 cents of every dollar after paying for the direct cost of its drinks and food. Meanwhile, the other 40 cents goes to ingredients and the people who prepare them.
How to Calculate Net Profit Margin Step by Step
Gross margin is only half the story, since the café still has to pay rent, wages, bills and tax. Here is the formula for the second margin:
Net profit margin = Net profit ÷ Revenue × 100
Step 1: Start With Your Gross Profit
Use the number you just found. Here, the café’s gross profit is $30,000.
Step 2: Subtract Operating Expenses
Operating expenses are the everyday costs of running the business that aren’t part of COGS. For example, suppose the café’s monthly costs look like this:
| Expense | Amount |
| Rent | $5,000 |
| Wages (front of house and admin) | $10,000 |
| Marketing | $2,000 |
| Utilities and other costs | $2,000 |
| Total operating expenses | $19,000 |
So $30,000 − $19,000 = $11,000 operating profit.
Step 3: Subtract Interest and Tax
Next, take off the cost of borrowing and the tax on your profit. Say the café paid $1,000 in loan interest and $2,000 in tax.
$11,000 − $1,000 − $2,000 = $8,000 net profit
Step 4: Divide Net Profit by Revenue
Finally, divide and multiply by 100.
$8,000 ÷ $50,000 = 0.16, and 0.16 × 100 = 16%
In the end, the café keeps 16 cents of every dollar of sales. That’s the real profit, after every bill is paid.
Gross Profit Margin vs Net Profit Margin at a Glance
Here is how the two measures compare, using the café numbers above.
| Gross profit margin | Net profit margin | |
| Formula | (Revenue − COGS) ÷ Revenue × 100 | Net profit ÷ Revenue × 100 |
| Costs included | Direct costs only | All costs, interest and tax |
| Café example | 60% | 16% |
| What it tells you | How well you price and produce | How much you really keep |
| Best used for | Pricing and cost control | Overall business health |
Notice the gap between 60% and 16%. In fact, that 44-point gap is where overheads, interest and tax live. If the gap keeps growing, your overheads are growing faster than your sales.
What Is a Good Number When You Calculate Gross Profit Margin?
There’s no single “good” number, because margins vary widely by industry. For example, a grocery store usually runs on thin margins and sells high volumes, while a software company or consultancy often keeps much more of each sale.
So instead of chasing a universal figure, use three comparisons:
- Your own history: Is the margin rising or falling month to month?
- Your target: Did you hit the margin you planned when you set prices?
- Similar businesses: Industry associations and accountants can share typical ranges for your sector.
Trends matter more than any one month, since a slowly shrinking margin is an early warning, even when profit still looks healthy.
Margin vs Markup: Don’t Mix Them Up
Many owners confuse these two, so the mistake can quietly wreck pricing. Margin is profit divided by selling price. Markup is profit divided by cost.
Using the café’s totals, gross profit is $30,000, revenue is $50,000 and COGS is $20,000:
- Gross margin: $30,000 ÷ $50,000 = 60%
- Markup: $30,000 ÷ $20,000 = 150%
Same business, same profit, but very different percentages. As a result, a 50% markup does not give you a 50% margin. If you want a particular margin, work backwards from the selling price, not the cost.
Common Mistakes When You Calculate Gross Profit Margin
Even simple formulas go wrong when the inputs are off, so watch for these slips.
Leaving costs out of COGS. If direct labour or packaging is missing, your gross margin looks better than it really is.
Putting overheads into COGS. Rent and marketing belong in operating expenses. Otherwise, you can’t compare periods fairly.
Using gross sales instead of net sales. Returns and discounts reduce your real revenue, so subtract them first.
Mixing time periods. Always match revenue and costs from the same month or quarter. Otherwise, the percentage means nothing.
Forgetting owner pay. If you work in the business, include a fair wage for yourself. Otherwise, your net margin looks bigger than reality.
Stopping at the percentage. A margin is a starting point. Ask why it moved, and what you’ll do about it.
How to Improve Your Gross and Net Profit Margins
Once you can calculate gross profit margin and net margin, you can start to move them. However, different levers affect each one.
To lift gross margin
- Review your prices. Even a small increase can add a lot to gross profit.
- Negotiate with suppliers or compare quotes every few months.
- Cut waste and returns, since they raise your effective cost per sale.
- Push your highest-margin products and services harder.
If you’re not sure where to start with prices, see our pricing strategy guide.
To lift net margin
- Go through overheads line by line each quarter and cancel what you don’t use.
- Refinance or repay expensive loans to cut interest.
- Automate repetitive admin so staff time goes to selling.
- Plan for tax early, so there are no nasty surprises.
For more small business finance guidance, the U.S. Small Business Administration offers free tools and training for owners.
Frequently Asked Questions
What is the formula to calculate gross profit margin?
Subtract your cost of goods sold from revenue, divide the result by revenue, and multiply by 100. For example, with $50,000 in revenue and $20,000 in COGS, the gross profit margin is 60%.
What is the formula for net profit margin?
Divide net profit by revenue and multiply by 100. Net profit is what remains after all expenses, including COGS, operating costs, interest and tax.
Can a business have a high gross margin but a low net margin?
Yes. That happens when overheads, interest or tax eat most of the gross profit. A café with a 60% gross margin can still end up with a thin net margin if rent and wages are high.
How often should I calculate my margins?
Monthly is a good habit for most small businesses. Seasonal businesses may also want a quarterly and a year-on-year view.
Is gross profit the same as gross margin?
Not quite. Instead, gross profit is a money amount, such as $30,000. Gross margin, or gross profit margin, is that amount as a percentage of revenue, such as 60%.
Final Thoughts: Calculate Gross Profit Margin Every Month
Profit isn’t a feeling. Instead, it’s a number you can measure. When you calculate gross profit margin and net profit margin side by side, you learn whether your pricing works and whether your overheads are under control.
Start with last month’s figures. First, find revenue and COGS. Then work down to net profit and compare the two percentages. Write them in a simple table, and repeat it next month.
After three months, you’ll see a pattern. In turn, that pattern shows what to fix first, whether it’s prices, supplier costs or overheads.