Two startups can have the same $2 million in the bank and completely different stories. One is spending $150,000 a month with no revenue. The other is spending $150,000 but collecting $100,000. The first has about thirteen months of runway. The second has a net burn of $50,000 and closer to forty. Same bank balance, different clock. That gap is why investors ask for gross burn and net burn, not just one number.
Gross burn is the cash your company spends in a period before any revenue comes in. Think payroll, contractors, software, rent, cloud hosting, marketing, travel, and interest on debt. If money leaves the bank account for operations, it belongs in gross burn. Net burn is gross burn minus the cash you collected from customers. Some teams calculate it as the actual decline in cash for the month, which also captures financing, taxes, and one-off payments.
Example: a seed-stage software company pays out $120,000 in March. It collects $70,000 from customers. Gross burn is $120,000. Net burn is $50,000. If the bank balance fell by $62,000 because of an annual insurance payment, that $62,000 is the cash burn for the month, but it is not the same as operating net burn. Label your numbers so nobody has to guess.
Gross burn shows the size and shape of the cost base. It answers: how expensive is this machine to run? Net burn shows how much of that machine customers are paying for. It answers: how close is this business to funding itself?
A company with a low net burn but a huge gross burn may be buying revenue with sales and marketing, or living on a few large prepayments. A company with a low gross burn but a high net burn may simply be pre-revenue, which is fine at the right stage. Investors read the pair together because either number alone can flatter or frighten.
Use gross burn when revenue is small, lumpy, or not yet meaningful. Pre-seed and seed companies often have no reliable revenue, so net burn is just gross burn with extra noise. Gross burn is also the right lens during a cost reset, a hiring freeze, or a pivot. If you cut $30,000 a month from payroll, that change shows up immediately in gross burn. It does not get hidden by a good collections month.
Gross burn is useful for comparing teams and planning budgets. A head of engineering can see the fully loaded cost of a squad. A founder can decide whether to add two salespeople or one. Investors use it to test whether spending matches the plan they funded.
Once revenue is recurring and reasonably predictable, net burn becomes the headline. It tells you how much external cash you need each month to keep going. It drives runway, dilution, and the timing of the next raise.
But use a trailing average. A single month of net burn can be distorted by an annual prepayment, a late invoice, or a tax payment. Three to six months of data is more honest than one tidy month.
Revenue on a dashboard is not the same as cash in the bank. A customer may sign a $120,000 annual contract in December and pay upfront. Your accounting system recognizes $10,000 per month. Your bank account gets $120,000 in December. Net burn looks wonderful that month and terrible the next, when no cash arrives but the team keeps spending.
Investors know this. They will ask about bookings, recognized revenue, collections, deferred revenue, and accounts receivable. If you present only net burn, you may look better than reality for one month and worse for the next. If you present only gross burn, you may look reckless when a large prepayment is sitting in the bank.
The fix is a simple bridge. Show gross burn, then show cash collected from customers, then show the net. Add a note for anything unusual: annual prepays, delayed payments, one-time hardware purchases, or seasonality. That gives investors the full picture without forcing them to reconstruct it.
Lead with the stage. A pre-revenue company should lead with gross burn and months of runway. A company with repeatable revenue should lead with net burn, then show gross burn underneath. Use consistent definitions every month and never switch methods to make a number look better.
A practical update includes:
If an investor asks, “What’s your burn?” you can answer in two lines: “Gross burn is $120,000. Net burn averaged $48,000 over the last quarter, but that includes a $60,000 annual prepay, so normalized net burn is closer to $68,000.” That answer builds trust because it shows you know your own cash flow.
Reconcile the bank account first. Categorize every outflow. Calculate gross burn from the expense side. Calculate net burn from the cash side, then reconcile the difference. Write a short note explaining any gap larger than a few percent. Keep a rolling three-month average, and update your runway with both a base case and a slower-revenue case.
Do this before anyone asks. The founders who handle burn conversations well are not the ones with the lowest number. They are the ones who can explain the number, the timing, and the plan. This is general education, not accounting or investment advice; for decisions about runway, fundraising, or financial reporting, check with a qualified accountant or CFO.
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