How to Know Whether Last Month Was Actually Profitable

Two owners describe the same month. One says it was excellent — the account is fuller than it has been all year. The other says it was poor — takings were down. Both are looking at their bank balance, and neither has answered the question.

Your bank balance tells you what happened to cash. Profit is a different question, and the gap between them is where most business surprises live.

Why a good month can leave you short

You sold well. But you also restocked heavily, so much of the money went straight back out. That stock is not an expense yet — it is still yours, sitting on the shelf. Your bank looks bad; your profit is fine.

Or the reverse. A quiet month, but you collected on invoices from three months ago and did not restock. The account looks healthy. You made very little.

Neither is a mistake. They are just two different questions, and you need both answered.

The four numbers

1. Revenue — what you sold

Goods sold in the period, whether or not the customer has paid. If you count only what was collected, a month where a big customer pays late looks like a month where you sold nothing.

2. Cost of sales — what those goods cost you

Not what you spent on stock this month. What the things you sold cost you to buy. This is the number most owners estimate, and estimating it is why gross margin is usually wrong.

3. Gross margin — the gap

Revenue minus cost of sales, as a percentage. This is the single most useful number in a trading business. Watch it monthly. When it moves, something real has changed: your buying price, your selling price, your mix, or your shrinkage. A margin that drifts down while sales hold steady is usually leakage.

4. Operating expenses — the cost of being open

Rent, salaries, fuel, data, transport. Largely fixed, which is what makes them dangerous — they continue at the same rate through a slow month.

Revenue minus cost of sales minus operating expenses is your profit. Everything else is commentary.

Why these are hard to get by hand

Not because the arithmetic is difficult — because the raw data usually is not there. Cost of sales requires knowing what each item cost, which requires purchases entered against items. Revenue requires every sale captured. Margin requires both to be right at once.

This is what double-entry bookkeeping is for. Not to satisfy an accountant, but so that these four numbers fall out of your ordinary trading records instead of being reconstructed at year end from memory and a bag of receipts.

A monthly habit worth twenty minutes

On the first working day of each month, look at four things: revenue, gross margin percentage, operating expenses, and total owed to you by customers.

Compare each to the previous month and the same month last year. You are not looking for precision. You are looking for the one line that moved and asking why.

Owners who do this catch problems in weeks. Owners who wait for year-end accounts find out in nine months, when the cause is no longer traceable.

Frequently asked questions

My accountant does this annually — is that not enough? Annual accounts are for tax and compliance. They are far too late to run a business by; by the time they arrive the quarter that went wrong is long gone.

What is a good gross margin? It varies enormously by trade, so an external benchmark is close to useless. Your own margin last month is the comparison that matters.

I have several branches — should I look at them together? Look at both. Group totals hide a branch that is losing money while the others carry it.