Gross margin is the percentage of revenue left after a business pays the direct costs of making or buying what it sells. It strips out overheads and finance items and focuses on core unit profitability.
You will often see it presented alongside gross profit. Gross profit is revenue minus cost of goods sold. Gross margin expresses that gross profit as a percentage of revenue, which makes comparisons easier across products, periods and companies.
What goes into revenue and cost of goods sold
On the top line, companies usually start from net sales. That is invoiced sales after returns, allowances and discounts. Using net sales avoids flattering the margin with revenue that will not be collected.
Cost of goods sold, often shortened to COGS or cost of sales, captures the direct costs tied to producing or acquiring the goods and services delivered in the period. What counts as direct varies by business model:
- Manufacturers typically include raw materials, components, factory labour and a share of production overheads such as utilities and quality control.
- Retailers and wholesalers include the purchase cost of inventory, inbound freight and import duties. Some include warehouse handling. Outbound delivery to customers might sit in COGS or in operating expenses depending on policy.
- Software and subscription businesses often treat hosting, third party platform fees, customer support and implementation staff as cost of sales.
Accounting frameworks permit judgement here, so two companies in the same sector can classify similar costs differently. Always read the definitions in the notes to the accounts when you compare margins.
How to calculate gross margin
There are two simple steps.
- Find gross profit: gross profit = revenue minus cost of goods sold.
- Divide by revenue: gross margin = gross profit divided by revenue, then show it as a percentage.
Example: a company reports £1,200,000 of net sales and £780,000 of cost of sales. Gross profit is £420,000. Gross margin is £420,000 ÷ £1,200,000 = 35.0%.
Some reports quote gross margin in basis points as well as percentages. A rise from 34.2% to 35.0% is an 80 basis point improvement.
Why gross margin matters in practice
Gross margin is a quick read on pricing power and unit costs. If it trends higher, the business may be raising prices, improving mix, cutting input costs or becoming more efficient. If it falls, competitive pressure, discounting, cost inflation or an unfavourable product mix could be at work.
It also connects directly to operating leverage. A higher gross margin means more of each extra pound of sales is available to cover fixed costs like head office staff, R&D and marketing, and then flow into profit. That is why small margin moves can have an outsized effect on earnings when revenue is growing.
For traders and investors, gross margin helps frame expectations around future profitability and cash generation. In valuation models, a sustainable margin level is often a key assumption. In credit work, it can signal resilience to input cost swings.
Comparing margins across industries
There is no single good or bad gross margin level. It is shaped by the economics of the sector:
- Grocery retail often runs low margins with high volume and rapid inventory turns.
- Luxury goods and branded pharmaceuticals tend to earn high margins due to brand power and patents.
- Software and digital platforms can show very high margins once the product is built, because the cost to serve an extra customer is low.
- Commodity producers see margins swing with market prices for the output and for inputs like energy.
Seasonality and product mix complicate comparisons. A retailer’s margin may climb in a festive quarter if higher margin categories sell well. A hardware maker may see margin dip at the start of a product cycle if it launches with promotional pricing. Look at multi year trends and peer groups rather than a single quarter in isolation.
Gross margin vs mark up and operating margins
Gross margin is often confused with mark up. They answer different questions.
- Gross margin asks what share of sales price is left after direct costs. Formula: gross profit divided by revenue.
- Mark up asks how much you added to cost to set the selling price. Formula: gross profit divided by cost of goods sold.
These give different percentages. If you buy something for £70 and sell it for £100, gross margin is £30 ÷ £100 = 30%. Mark up is £30 ÷ £70, about 42.9%.
Do not mix gross margin with operating margin or EBITDA margin. Those subtract operating expenses such as salaries for sales and admin teams, marketing, rent and product development. Gross margin sits higher up the income statement and is meant to isolate direct unit economics before overheads.
Common pitfalls and adjustments
Several factors can cloud the picture if you take the number at face value:
- Classification choices. Fulfilment costs, outbound shipping, warranties and customer support can be shown in COGS or below the gross profit line. This changes the margin mechanically without altering the underlying economics.
- Inventory accounting. Methods such as FIFO and weighted average affect the cost recognised in the period, especially when input prices are moving.
- One offs. Inventory write downs, production issues or a large launch promotion may hit a single period. Companies sometimes flag these and provide an adjusted margin.
- Revenue recognition. Marketplaces may recognise gross revenue or only the commission. The policy makes the denominator bigger or smaller and shifts the margin level, even if cash earned is the same.
- Currency. If revenue is in one currency and costs in another, exchange rate moves can help or hurt margin between periods.
When management guides to margin, pay attention to the wording. A promise to expand gross margin might rely on mix shifts, procurement savings, price rises or a change in classification. Each has different durability.
A simple worked example
Imagine a small online retailer in a quarter:
- Orders invoiced: £1,000
- Returns and discounts: £50
- Net sales: £950
- Inventory purchases for items sold: £560
- Inbound freight and duties: £40
Cost of goods sold is £600. Gross profit is £350. Gross margin is £350 ÷ £950, which is 36.8%.
Now imagine a subscription software firm for the same period:
- Subscription revenue: £100
- Hosting and third party platform fees: £8
- Customer support and onboarding staff costs: £12
Cost of sales is £20. Gross profit is £80. Gross margin is 80%. The high margin does not mean the software firm is more profitable overall. It still needs to cover sales, marketing and product development, which are usually heavy up front. The retailer’s lower margin can still produce strong earnings if it turns stock quickly and keeps overhead lean.
Where you will see gross margin used
Management teams discuss gross margin in results calls, trading updates and investor days because it links strategy to numbers. Price increases, product launches, input hedging and supply chain changes all show up here first.
Analysts build margin bridges to explain moves between periods, splitting the change into price, volume, mix and cost. Equity research notes often compare peers on gross margin stability as well as level, then tie that to valuation multiples. In fundamental analysis, expected gross margin is one of the anchors for revenue quality and long term return on capital.
For operators, gross margin is a control metric. It helps set pricing, plan promotions, judge supplier terms and prioritise engineering work that trims unit costs. Used consistently with clear definitions, it keeps commercial decisions tied to unit economics rather than just top line growth.