Operating expenses (OpEx)

The costs of running the business that do not scale directly with each sale — salaries, rent, software, marketing, legal.

Example

Your product engineers, your office, your accountant.

OpEx is what you actually control month to month. It is where a cut to extend runway comes from.

COGS (Cost of Goods Sold) — The direct costs of delivering your product — the costs that rise with each additional customer.
Burn rate — How much cash the company spends per month. Gross burn is everything going out; net burn is what goes out after revenue comes in.
Income statement (P&L) — A statement of revenue, costs and profit over a period. Revenue − COGS = gross profit; gross profit − OpEx = operating profit.
EBITDA — Earnings before interest, tax, depreciation and amortisation — a rough proxy for operating profitability.

Building a chart of accounts — The twenty-odd categories every transaction lands in. Get this right once and every report you ever run is useful; get it wrong and no amount of software helps. (12 min)
Contractor or employee? — Two legally distinct arrangements with different tax, control and IP consequences. Getting it wrong is a real risk. (12 min)
Vendors, tools and recurring costs — Subscriptions accumulate silently. An annual audit routinely finds 20–30% of tool spend buying nothing. (10 min)
Revenue, costs and profit — The three numbers everything else is built on, and the difference between the money that comes in and the money you keep. (10 min)
Reading an income statement — The P&L, top to bottom. Fifteen minutes and you will never be lost in an accountant's email again. (12 min)
Building a startup budget — A budget is not a prediction. It is a decision about what you will spend, made once, calmly, instead of forty times under pressure. (12 min)