Two businesses, one 62% bigger than the other, and the big one takes home less than a third as much. Turnover measures activity. Margin measures whether the activity was worth doing.
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Ask a small business owner how the year is going and you will usually get a turnover figure. It is the number in the pitch, the number that feels like the score. It is also the number that tells you least about whether the business is working.
It is worth being precise about what it is, because it gets used loosely. Turnover is the income the business generates from its ordinary sales or services before any costs are taken off. It is not the money that landed in the bank, which is a different figure again: it moves with when customers actually paid, with VAT, and with anything else passing through the account.
Turnover measures activity. Margin measures whether that activity was worth doing. A business can grow its turnover every year for a decade and be worse off at the end of it, and that is not a hypothetical: it is a common pattern we see.
Worth being precise here, because the shorthand version of this point is wrong. For Income Tax and Corporation Tax, it is generally taxable profit rather than turnover that determines the tax charge. Taxable profit may differ from the profit shown in the accounts because tax rules require various adjustments. For businesses using traditional accounting, for example, depreciation is normally disallowed for tax and qualifying capital expenditure may instead receive capital allowances. Different rules apply to sole traders and partnerships using the cash basis.
With cash basis you only record income or expenses when you receive money or pay a bill.
That single sentence is why turnover and the bank balance are two different numbers, and why neither of them is your margin. On the cash basis the timing of a payment decides the year it falls in; on traditional accounting the invoice date does. Either way, what you billed, what you banked and what you kept are three separate questions, and only the third one tells you whether the work was worth doing.
Turnover is not irrelevant to tax, though. VAT obligations can be based on taxable turnover, and HMRC's registration test is stated in turnover.
your total taxable turnover for the last 12 months goes over £90,000 (the VAT threshold)
Note what that rule measures and what it ignores. It is a rolling twelve-month test on turnover, with no reference to profit anywhere in it, so turnover growth can create a VAT registration obligation even where profits have not improved. The financial effect of registering then depends on the business's customers, its pricing and how much input VAT it can recover: a business selling to VAT-registered businesses may barely notice, and one selling to the public can find that 20% has to come out of its own margin or go on its prices.
Two businesses, same sector, same year. Here is why turnover on its own cannot tell them apart.
| Business A | Business B | |
|---|---|---|
| Turnover | £420,000 | £260,000 |
| Cost of sales | £340,000 | £150,000 |
| Gross margin | 19.0% | 42.3% |
| Overheads | £68,000 | £72,000 |
| Profit | £12,000 | £38,000 |
Business A is 62% bigger and takes home less than a third as much. It is also far more fragile: a two-point slip in its margin wipes out most of the profit, where Business B could lose five points and still be comfortable.
If all you have is the turnover line, A looks like the success story. It is also the one with least room for anything to go wrong. Cash flow turns on more than margin, so this is not a prediction about which business fails first; it is that A has to keep everything else going right, and B does not.
Gross margin is what remains after the direct costs of delivering the sale are deducted. Overheads are then deducted to arrive at the business's overall profit.
Margin often does not collapse overnight. It leaks, which is why it is so easy to miss without something measuring it monthly. The usual routes:
Every one of those is invisible in a turnover figure and obvious in a margin by month. The mechanism is always the same: costs rise, prices do not follow, and the difference comes out of the margin. A business in exactly that position can be selling the same volume at the same prices and reporting the same revenue as last year while quietly earning less on every job. It is worth checking whether the same thing is happening in your business, because turnover is the one number that will not tell you.
Annual accounts can tell you how the business performed, but if margin is only reviewed when those accounts are prepared, you may be looking at trading performance several months after it happened. That is fine for filing and of limited use for running a business.
A monthly profit and loss turns margin into something you can steer by. If March was two points down on February you can ask why in April, while the answer is still findable and the customer is still on the phone. Getting that into a weekly and monthly routine is what makes it happen at all.
The timing argument matters most when trading conditions are difficult. If demand is soft and costs are firm, growing sales into a shrinking margin is the specific way a business gets busier and poorer at the same time, and it is the version of trouble that feels like success right up until the year-end accounts arrive. Twelve monthly readings would catch it by about March. One annual reading catches it the following autumn.
We once picked up a client who had been trading five years and had never seen a profit and loss by month. Not because anyone had refused; it had simply never been produced. The information she needed to price her work properly had existed in her records the whole time and nobody had ever put it in front of her.
You do not need a dashboard. Four figures a month, consistently, will do more than any amount of analysis done once a year.
Margin tracking depends on the bookkeeping underneath it being right, and this is where it usually falls down. If costs of sale and overheads are mixed together in the nominal ledger, a margin figure is not wrong so much as meaningless.
The most common faults we correct are income posted to expense codes and expenses posted to income codes, and bank accounts that have not been reconciled for long enough that nobody is confident in any of it. A poorly structured chart of accounts can contribute to the problem, as can inconsistent coding, automated bank rules and unreconciled transactions, which is one reason we take setting the software up properly seriously. Both can usually be corrected, although the amount of work depends on the condition of the records. Until they are, they make every figure above them untrustworthy.
Once the ledger is sound, a monthly set of management accounts becomes much easier to produce consistently once the underlying bookkeeping is reliable, and it is the difference between finding out in month three and finding out in month twelve.
Turnover is broadly the income generated from the business's ordinary sales or services before costs are deducted, normally excluding VAT, and it is different from the amount of cash received into the bank. Margin is what was left of it after the costs of delivering the work. Turnover measures activity; margin measures whether that activity was worth doing, which is why a business can grow its turnover for a decade and be worse off at the end.
For Income Tax and Corporation Tax, it is taxable profit rather than turnover that normally determines the tax charge. Turnover is not irrelevant to tax, though: VAT obligations can be based on taxable turnover, and the VAT registration threshold is a turnover test rather than a profit one.
Gradually, and in ways invisible in a turnover figure: prices that were set years ago against costs that have moved, one large customer on special terms, scope creep on jobs quoted at less time than they take, supplier increases absorbed one at a time, and product lines kept on that no longer cover their costs.
It varies enormously by sector, so a single benchmark is not much use. What is useful is your own margin as a trend by month, because a two-point slip in your own figure is meaningful regardless of what anybody else achieves.
Annual accounts can tell you how the business performed, but if margin is only reviewed when those accounts are prepared, you may be looking at trading performance several months after it happened. Monthly figures let you ask in April why March was down on February, while the answer is still findable.
Four things: gross margin percentage as a trend, margin by job or product or customer type if you have more than one kind of work, overheads as a share of turnover, and your break-even point. Most owners have never calculated break-even and are surprised by it.
Every figure on this page was checked against the sources above on . Rates and thresholds change. If you are reading this long afterwards, check the current position before you act on it.
If your bookkeeping is up to date but you are not seeing gross margin, overheads and profitability clearly each month, we can help put the reporting in place. Talk to us about bookkeeping and management accounts.
What this touches
A new 40% first-year allowance arrived on 1 January 2026 and has been reported almost everywhere as good news for business investment. For a business spending inside the £1m Annual Investment Allowance it is a worse claim than the one it already had, and the change that does land is the one underneath it.
From April 2028 trading small companies and micro-entities have to file a profit and loss account, abridged accounts disappear, and the web and paper routes for filing accounts close. There is an opt-out from publishing the figures, and a lot of what you will read still gives the wrong year.
Identity verification is now mandatory for company directors and people with significant control. The transition period runs to November 2026, but there is no single deadline that applies to everyone: yours depends on your role and your circumstances. Miss it and your company cannot file its confirmation statement.
