Sales are up, orders are moving, and yet there’s never as much left at the end of the month as you expected. When that happens, the question of gross margin vs net margin becomes more than a vocabulary lesson. These two numbers point to different parts of the business, and knowing which one is weak tells you where to look first.
Here’s how each margin works, what tends to push each one down, and how product sellers can use them to make clearer decisions.
What Gross Margin Measures
Gross margin shows how much of each sales dollar is left after paying for the products you sold.
The formula is simple: subtract cost of goods sold (COGS) from revenue, then divide by revenue.
Say you sell a product for $40, and your landed cost (the product plus freight to get it to you) is $16. Your gross profit on that sale is $24, and your gross margin is 60%.
Gross margin is really about your product economics. It reflects your pricing, your supplier costs, and how much you’re discounting. It doesn’t include rent, payroll, software, or ad spend.
What Net Margin Measures
Net margin shows how much of each sales dollar is left after every expense. That includes COGS, operating costs, interest, and anything else on the profit and loss statement.
The formula is net income divided by revenue.
Net margin is the bottom-line view. It answers a different question: after running the whole business, how much did you actually keep?
Gross Margin vs Net Margin: Why You Need Both
Looking at only one of these can steer you wrong.
Here’s a simple example. A store brings in $50,000 in a month with a 55% gross margin, so $27,500 is left after product costs. Then it spends $12,000 on ads, $8,000 on payroll, and $6,000 on software, fees, and everything else. That leaves $1,500, a net margin of 3%.
The gross margin looks healthy. The net margin doesn’t. In this case, the products aren’t the problem. The cost of running and growing the business is eating most of the gross profit.
Now flip it. If the gross margin were only 25%, even a very lean operation would struggle to show much profit. Cutting overhead would help a little, but the real fix would be in pricing, product cost, or product mix.
That’s the practical value of tracking both:
- A weak gross margin points you toward pricing, suppliers, freight, discounts, and returns
- A healthy gross margin with a weak net margin points you toward overhead, ad spend, and fees
- Both weak at once usually means the business needs a closer look across the board
What Pushes Gross Margin Down
For product sellers, gross margin tends to slip quietly. Common causes include:
- Supplier price increases that never made it into your retail prices
- Rising inbound freight or duty costs
- Heavy or frequent discounting
- Higher return rates, especially when returned items can’t be resold
- A shift in sales toward lower-margin products
- Fulfillment costs climbing, if you include them in COGS
What Pushes Net Margin Down
Net margin is affected by everything above, plus the costs of operating the business:
- Advertising that grows faster than sales
- Software subscriptions that keep stacking up
- Payroll added ahead of the revenue to support it
- Merchant and marketplace fees, if they sit in operating expenses
- Interest on loans or credit lines
None of these are bad on their own. The question is whether they’re producing enough gross profit to pay for themselves.
Look at Margins by Channel and by Product
A blended margin for the whole business can hide a lot. A product that sells well on your own Shopify store might be much less profitable on Amazon or Walmart once marketplace fees and fulfillment costs are factored in. Wholesale orders often carry lower gross margins than direct-to-consumer sales, but they may cost less to fulfill and market.
Breaking margins out by channel, product line, or customer type helps you see where you’re actually making money. Our post on ecommerce accounting services for growing online stores explains why that level of detail starts to matter as you add sales channels. Wholesale brands can find more on this in our post about financial planning for wholesale brands.
Don’t Confuse Margin With Markup
These two get mixed up all the time, and the difference can throw off pricing.
Markup is based on cost. Margin is based on the selling price. In the earlier example, a $16 product sold for $40 has a $24 profit. That’s a 150% markup on cost, but a 60% gross margin on the sale.
If you set prices using a target markup but measure success using margin, the numbers won’t line up. Pick one way of talking about it with your team and stick with it.
Your Margins Are Only as Good as Your Books
Margins are calculated from your bookkeeping, so the inputs matter. A few things can distort them:
- Inventory purchases recorded as expenses when they’re bought, instead of moving into COGS as products sell
- Marketplace payouts recorded net of fees, which shrinks revenue and hides costs
- Fees or fulfillment costs bouncing between COGS and operating expenses from month to month
- Uncategorized transactions sitting outside the P&L entirely
If your margins look strange from month to month, check the books before changing your prices. If profit has been slipping and you’re not sure why, our post on five signs the problem may be hiding in your financial system is a good place to look next.
Using Margins to Make Decisions
Once your margins are reliable, they become a practical tool. You can use them to decide whether a price increase is necessary, whether a new channel is worth it, how much ad spend the business can support, or which products deserve more inventory.
Tracking gross margin and net margin as regular KPIs, rather than checking them once a year, makes it much easier to spot changes early.
At Build Your Books, we use customized KPIs to help clients see their strengths and spot problems sooner, and our CFO services include budgeting, cash flow tracking, and monthly meetings to talk through the numbers. You can see how those pieces fit together on our services page and meet the people who’ll be working with you.
If you want a clearer view of where your margins are going, start a conversation with our team. We’ll help you figure out which number needs attention first.