Gross margin is the percentage of revenue that remains after deducting the direct costs of delivering your services, showing how efficiently your agency turns sales into profit.
For agency founders, gross margin is calculated as (revenue minus cost of goods sold) divided by revenue, multiplied by 100. In a service business, cost of goods sold typically includes the salaries and contractor fees of the team directly working on client projects, plus any software or materials used exclusively for those projects. It does not include overheads like rent, marketing, or admin salaries.
A healthy gross margin for a UK agency usually falls between 40% and 60%. If your margin is below 30%, you are likely undercharging, over-servicing, or carrying too many non-billable hours. Above 70% is rare for service businesses and may indicate you are not investing enough in delivery quality.
To calculate your agency's gross margin accurately, you need to track time and costs per project. For example, if a client pays you £10,000 for a campaign, and your direct team costs (salaries, NI, pension, and software) total £4,500, your gross profit is £5,500. Your gross margin is 55%. This figure tells you how much you have left to cover your overheads and generate profit before tax.
Gross margin differs from net profit margin. Net profit margin deducts all operating expenses, including rent, utilities, marketing, and your own salary. Gross margin focuses purely on the efficiency of your service delivery. Improving gross margin often means raising prices, reducing project scope creep, or increasing team utilisation rates.
For UK agencies, the corporation tax rate (19% for profits under £50,000, 25% for profits over £250,000) applies to your net profit, not your gross margin. But a strong gross margin gives you the buffer to absorb tax liabilities, pay dividends (taxed at 8.75% to 39.35% depending on your bracket), and reinvest in growth.
When this matters for agency founders
Gross margin is the single most important metric for pricing decisions, profitability analysis, and investor conversations. If you are raising prices, hiring new team members, or considering a sale of your agency, gross margin tells you whether your core service model is sustainable. Track it monthly, not annually, and benchmark against the 40-60% target range for UK agencies.