Most business owners open their P&L, look at the bottom line, feel briefly good or bad, and close it. That's not a review — that's a mood check. A real monthly review takes about ten minutes once you know which five numbers to interrogate. Here they are, in the order we check them for our own clients.
Comparing this month to last month mostly measures seasonality — December versus November tells you it's December. Comparing this June to last June removes the seasonal noise and answers the question that matters: is the business actually growing?
Look at the trend across a few months of year-over-year comparisons, not one data point. A single soft month is weather; three in a row is climate, and climate is what you plan around.
Gross margin is what's left of revenue after the direct costs of delivering it, expressed as a percentage. It's the health reading dollar figures hide: revenue can grow while margin quietly erodes, which means you're working harder to keep less.
A drifting margin always has a cause — supplier prices creeping, a discount that became permanent, jobs quoted before costs rose, or one product line dragging down the blend. The monthly check is what catches the drift in month two instead of month twelve, while the fix is still a conversation with a supplier or a price list update.
Take total people costs — wages, source deductions, benefits, contractors doing the work of staff — and divide by revenue. Healthy ranges differ wildly by industry, so the benchmark that matters most is your own history.
Watch the direction. The ratio climbing for a stated reason — you hired ahead of growth you can name — is a plan. The ratio climbing with no story attached is the single most common way a profitable small business becomes an unprofitable one, one reasonable-sounding hire at a time.
Run your eye down every expense line and ask one question: does this number look like it usually looks? You're hunting for three species — the line that jumped without a reason you can name, the subscription that's still billing for software nobody opens, and the expense sitting in a category where it doesn't belong.
That third one matters more than people think. Miscoded expenses make every other number on this list quietly wrong, and they're the kind of thing a monthly review catches in minutes and a March cleanup discovers by the dozen. If your P&L categories are too vague to scan — one giant "General expenses" line — that's a bookkeeping fix worth making first.
The last check is the one that catches owners by surprise: put net profit next to what you personally withdrew from the business this month. Profit is an accounting result; your draws come out of cash. When withdrawals consistently exceed profit, the business is shrinking to pay you — a fact the P&L alone won't announce, because draws don't appear on it.
This is where the P&L needs its partner: the balance sheet is what reveals whether the business is building or bleeding, and we've written about why the balance sheet deserves equal attention. Review them together and the whole picture snaps into focus.
The catch behind all five numbers: they're only worth checking if they're current and reconciled. A P&L that's four months behind answers questions you needed answered in the winter. This ten-minute review is the payoff of monthly bookkeeping — the books exist so that you can read them, notice things early, and act while acting is cheap.
The takeaway: five numbers, ten minutes, every month — that's the whole discipline. If your books aren't current enough to make it possible, book a free consultation and we'll fix that first.
This post is general information, not tax advice for your specific situation.
