You can run a profitable business for years and never properly read the one document that proves it. The profit and loss account, the statement that shows what your business earned and spent over a set period, sits in your accounting software mostly untouched. Owners glance at the bank balance instead. The bank balance does not tell you whether the business actually works.
The problem most SMEs face
Most owners read the P&L from the bottom up. They find net profit, the money left after every cost, and stop there. They skip gross profit, the money left after the direct cost of the things they sell. That gap matters. A business can post a decent net profit while its gross margin quietly shrinks, and the owner will not notice until the trend turns painful. The UK has more than five million small businesses, and many were started by people who never trained in finance. One survey put limited or no financial literacy at the start of trading at around two in five owners. That figure is from the US and illustrative, but the pattern is familiar here.
What good looks like
A well run SME reads the P&L top to bottom every month, not once a year across the accountant’s desk. Revenue at the top. Cost of sales next. Gross profit. Then overheads. Then net profit at the bottom. The owner knows two numbers without checking: gross margin and net margin.
Take an illustrative shop. Revenue is £30,000 a month, cost of sales is £20,000, so gross profit is £10,000, a 33% gross margin. Overheads of £8,000 leave a net profit of £2,000. Now let cost of sales drift to £22,000. Gross profit falls to £8,000 and net profit reaches zero. Same revenue, a small cost change, profit gone. The bottom line on its own would never explain why.
A practical step you can take today
- Open your P&L for last month and the same month a year ago. Put them side by side.
- Find five lines: revenue, cost of sales, gross profit, overheads, net profit. Your software may call them turnover, cost of goods sold, or operating expenses.
- Work out gross margin: gross profit divided by revenue, times 100.
- Work out net margin: net profit divided by revenue, times 100.
- Compare the two periods. Any line that moved more than a few percent, ask why before you move on.
- Check that cost of sales holds direct costs only. A misfiled overhead distorts your gross margin and hides the real problem.
What to watch out for
One-offs flatter the picture. A single large order or a VAT refund can make a weak month look strong, so strip it out before you judge a trend. Then there is the cash trap: the P&L records a sale when you invoice it, not when the money lands, so you can show a profit and still have an empty account. Finally, watch categorisation. A wages line sitting in cost of sales instead of overheads makes your core trading look worse than it is.
The rules are shifting too. The government planned to make small companies file a profit and loss account from 2027, moved that to April 2028, then paused the whole reform in January 2026. For now, filleted accounts stay.
Reading the P&L is the first step. Knowing what to do when gross margin slips is the harder one. FinanceMOT reads your numbers across four pillars, Liquidity, Profitability, Efficiency and Solvency, and turns them into a financial health score from 0 to 100, with KPI signals that flag the exact lines moving the wrong way. The executive summary points you to the margin to act on first, not just the fact that it changed.
