Small business numbers 101

You do not need accounting to run a small business. You need a handful of numbers and the honesty to look at them. This guide covers that handful: what each one means in plain English, how they fit together, and the one mistake beginners make with each.

The worked example throughout is deliberately simple and hypothetical: a one-person candle business. Swap in your own numbers as you read; the math is identical for a service, a product, or a subscription.

Revenue is not profit

Revenue is all the money customers pay you, before any costs come out. Sell 100 candles at $20 and your revenue is $2,000. It is the number that feels best and means least, because it says nothing about what you kept.

Profit is what remains after every cost: materials, fees, software, and eventually your own pay. A business can grow revenue every month while losing money the whole time. Whenever you hear an impressive revenue number, in your own spreadsheet or anyone else's story, the question is always the same: and what did it cost to make?

Gross margin: what each sale actually gives you

Take one sale. Subtract only the direct costs of delivering that sale, materials, shipping, payment processing. What is left is your gross margin, usually said as a percentage. A $20 candle that costs $8 in wax, wick, jar, and fees leaves $12, a 60% gross margin.

That $12 is not profit yet. It is the fuel that has to pay for everything else: your software, your insurance, your marketing, your time. Which is why margin matters more than revenue. A thin margin means each sale contributes almost nothing to the pile, and no volume of almost-nothing adds up fast.

Fixed and variable costs

Costs come in two kinds, and the difference matters. Variable costs grow with each sale, the $8 in the candle. Fixed costs arrive every month whether you sell or not: the website subscription, insurance, market-stall rent. Say those total $600 a month.

Fixed costs are the quiet danger for a new business, because they run while you are still learning to sell. Keep them brutally low at the start. Every fixed dollar you avoid is a dollar of sales you do not need just to stand still.

Break-even: the most clarifying number you can know

Break-even is where money in finally equals money out. The monthly version is one division: fixed costs divided by gross margin per sale. Our candle maker: $600 divided by $12 is 50 candles a month just to cover costs, before paying herself anything.

Run this division for your own idea and react to the answer honestly. Is your number 50, or 500? Can you name where those sales plausibly come from? This single number, computed in thirty seconds, kills more bad plans and confirms more good ones than any forecast. There is a second break-even too: how long until the business earns back what it cost to start. Know both.

Unit economics: does one sale even work?

Unit economics is the profit math of a single sale, including what it cost to win that customer. If you spend $10 on ads to sell one $20 candle with $8 of direct costs, that unit made you $2. If it took $15 of ads, the unit lost money, and more sales just lose more money.

The cost of winning a customer is usually called CAC, customer acquisition cost. Early on, yours may be near zero because your first customers come from people you know. It will not stay zero. The moment you pay for attention, ads, marketplace fees, referral bounties, the unit math has to absorb it.

Cash flow: profit has a timing problem

A profitable business can still die waiting to get paid. If you buy materials in January, deliver in February, and invoice on 30-day terms, the cash arrives in March, and rent was due all three months. That timing gap is cash flow, and it is why invoicing fast, taking deposits, and keeping a cash cushion are not accounting niceties but survival habits for a small business.

The habits that close the gap are boring and effective: invoice the day the work is done, ask for a deposit up front on anything custom or large, and keep at least one month of fixed costs sitting in the business account as a buffer before you count anything as spendable.

Price is the strongest lever you have

Notice what happens to every number above when the candle sells for $25 instead of $20. Margin per sale jumps from $12 to $17, break-even drops from 50 candles to about 36, and every ad dollar works harder. No other single change touches everything at once the way price does.

Beginners consistently underprice, because charging feels like a claim about their own worth. It is not. It is a claim about the customer's problem. Anchor your price to what the problem costs them, not to what the materials cost you, and let the first-customer test, covered elsewhere in this field guide, tell you if you are wrong.