The Percentage That Tells You If Your Pricing Works
Plenty of business owners know their sales figure and their profit figure. Far fewer can tell you, off the top of their head, what percentage of every pound of sales they actually keep after the cost of the thing they sold. That percentage is your gross margin, and it is one of the most useful single numbers in your accounts.
Gross margin matters because it is comparable. A profit figure on its own tells you very little. Is £70,000 of gross profit good? You cannot say until you know it came from £200,000 of sales rather than £2,000,000. Turn it into a margin and you have a number you can track over time, compare against last year, and hold up against businesses ten times your size. It is the difference between knowing how much you made and knowing how well you made it.
This guide explains gross margin in plain English, gives you the formula, walks through a worked example, and clears up the markup versus margin confusion that quietly costs small businesses real money. It also sets out what a healthy gross margin looks like, which depends far more on what you do than most online benchmarks admit.
What Gross Margin Actually Is
Gross margin is your gross profit expressed as a percentage of your revenue. Where gross profit is a pound figure, gross margin is the ratio behind it, and that small change is what makes it so useful.
The two are easy to mix up, so it is worth being precise. Gross profit is revenue minus the direct cost of what you sold, stated in pounds. Gross margin takes that same gross profit and asks what slice of every sales pound it represents. A business with £70,000 of gross profit on £200,000 of sales has a gross margin of 35 percent. The same £70,000 of gross profit on £700,000 of sales is a margin of just 10 percent, a completely different business even though the gross profit figure is identical.
The term gross profit margin means exactly the same thing as gross margin. You will see both used interchangeably, and neither is more correct than the other.
The Gross Margin Formula
The calculation has two short steps. First you work out gross profit, then you turn it into a percentage.
Gross profit = revenue − cost of goods sold
Gross margin = (gross profit / revenue) × 100
Revenue is your total sales for the period before any costs. Cost of goods sold, often shortened to COGS, is the direct cost of producing or buying what you sold. For a retailer that is the wholesale cost of stock sold. For a manufacturer it is raw materials and production labour. For a service firm it is the cost of the people doing the billable work. Crucially, COGS excludes your overheads such as rent, admin salaries and software, because those are not direct costs of a specific sale. They come out lower down the profit and loss account, when you move from gross profit to net profit.
You can fold both steps into one line if you prefer:
Gross margin = ((revenue − COGS) / revenue) × 100
A Worked Example
Take a small homeware retailer over a single year.
- Revenue: £200,000
- Cost of goods sold (wholesale cost of the stock it sold): £130,000
- Gross profit: £200,000 − £130,000 = £70,000
- Gross margin: (£70,000 / £200,000) × 100 = 35 percent
So for every £1 of sales, the retailer keeps 35p after paying for the stock, and that 35p is what has to cover all the running costs of the business: the rent, the wages, the marketing, and whatever is left over as net profit at the end.
Now watch what a small change does. Suppose a supplier raises prices and COGS climbs to £150,000 on the same £200,000 of sales. Gross profit falls to £50,000 and the gross margin drops to 25 percent. Revenue has not moved at all, yet the business now keeps a quarter of each sales pound instead of more than a third. That ten point fall has to be made up somewhere, either by raising prices, finding a cheaper supplier, or absorbing the hit out of net profit. This is exactly why margin is worth watching month to month rather than waiting for the year-end accounts to deliver the bad news.
Markup Versus Margin: The Trap That Costs Real Money
Here is the single most common and most expensive mistake we see around margins. Owners set their prices using markup, then assume the markup percentage is their margin. It is not, and the gap between the two is wider than most people expect.
Markup is profit measured against cost. Margin is profit measured against the selling price. Same pounds of profit, different denominator, very different percentage.
Say an item costs you £100 and you sell it for £150. Your profit is £50. The markup is £50 against the £100 cost, which is 50 percent. But the margin is £50 against the £150 sale price, which is only 33 percent. An owner who adds a 50 percent markup and believes they are running a 50 percent margin is overstating their margin by a third, and pricing as if there is more headroom than there really is.
The conversion catches people out, so here is the quick reference:
| Markup | Equivalent gross margin |
|---|---|
| 20% | 16.7% |
| 25% | 20% |
| 33% | 25% |
| 50% | 33.3% |
| 100% | 50% |
The lesson is simple. Decide what gross margin you need first, because the margin is what actually has to cover your overheads, then work the price back from there. Pricing on markup alone and hoping the margin looks after itself is how businesses end up busy and still short of cash.
What Counts as a Good Gross Margin
Search for a target gross margin and you will find figures thrown around as if they apply to everyone. They do not. A good gross margin depends almost entirely on your business model, and comparing across sectors is close to meaningless.
A grocery retailer might run a gross margin in the low single digits to low twenties and be perfectly healthy, because the model is built on high volume and fast stock turnover. A software business often runs gross margins north of 80 percent, because once the product is built, each extra sale costs almost nothing to deliver. A trades or construction business might sit somewhere in the 20s or 30s. A consultancy whose only real cost of sale is people might run very high margins on paper but face heavy overheads underneath. None of these is right or wrong. They are different shapes of business.
So the useful comparison is not against a generic benchmark, it is against three things: your own margin last year, your margin on different products or services, and the typical margin for businesses doing exactly what you do. A margin that is steady or rising relative to your own history is the signal that matters. A margin drifting down, even while sales grow, is the early warning that your pricing or your costs are moving in the wrong direction long before it shows up in your bank balance.
Our View: Gross Margin Is a Gauge, Not a Trophy
In our experience, the businesses that stay healthy are not the ones chasing the highest possible margin. They are the ones that watch their margin closely and react fast when it moves.
Gross margin works best as a gauge you read regularly, the way you would glance at a fuel level, rather than a number you calculate once a year and forget. A two or three point slide in gross margin is easy to miss in the day to day, but across a full year of sales it can be the entire difference between profit and loss. Owners who see that slide early can do something about it, renegotiate with a supplier, lift a price, drop a product that never really paid. Owners who only see it at year-end are reacting to damage that is already done. The number itself is simple. The discipline of actually looking at it, broken down properly and often enough to matter, is where the value is.
How IAK Can Help
We make your gross margin a figure you can trust and actually use. Accurate bookkeeping ensures your direct costs and overheads sit on the right side of the line, so your margin reflects reality rather than miscategorised expenses. Our management reporting breaks margin down by product or service and tracks it month to month, so a slipping line is caught early. And our accounting work produces a profit and loss account where gross margin, operating profit and net profit all tell a consistent, honest story.
If you are not certain whether your prices leave you the margin your business actually needs, that is exactly the question we can help you answer. Contact us and we will work it through with you.
Sources
- FRS 102, the financial reporting standard for most UK small and medium companies, which sets out how revenue and cost of sales are presented in the profit and loss account. Published by the Financial Reporting Council.
- HMRC guidance on business expenses if you are self-employed, relevant to separating direct costs from overheads.
- Office for National Statistics data on UK business profitability and output, useful background when benchmarking margins across sectors.