Cash Burn

A company has money in its account and uses it to pay salaries, rent, servers, and materials. At the same time, it takes in money from customers. When expenses exceed revenue, the balance shrinks every month. This exact monthly deficit is called cash burn. The term originates from the start-up world, but is also used by large technology companies. It says nothing about whether a company is good or bad, only about how quickly its cash reserves are dwindling.

How long the money will last

Cash burn gives rise to a second figure that is, in practice, even more important: runway. It describes how many months the available money will still last. The calculation is simple. You divide the balance in the account by the monthly loss. Anyone who has 24 million euros and burns 2 million per month has twelve months of time.

These twelve months are a hard deadline. If it expires without new money coming in, the company can no longer pay its bills. That’s why founders usually start talking to investors about a new funding round six to nine months in advance. Anyone who only starts in the last month negotiates from a position of weakness and gets worse terms.

The distinction between loss and cash burn is important. A loss is an accounting figure and also includes items where no money actually flows. Cash burn counts only real payments. A company can show a profit on paper and still be burning cash, for instance because customers don’t pay until three months later.

What goes into the calculation

Experts distinguish between two variants. Gross burn is the sum of all expenses in a month, meaning everything that leaves the account. Net burn subtracts revenue from that and is therefore the more meaningful figure. When the news talks about burn rate, it almost always means net burn.

At AI companies, the biggest line item is usually computing power. Training large language models runs for weeks on thousands of specialized graphics chips. Renting such computing capacity quickly costs double-digit millions. On top of that come high salaries for researchers and developers, who are fiercely contested in the job market.

A high cash burn is not automatically an alarm signal. What matters is what it produces. Anyone who spends money while building rapidly growing revenue is investing in the future. Anyone who spends a lot and stagnates has a problem. That’s why investors always look at burn and growth together, never at one figure alone.

The figure in news and quarterly reports

In reports about start-ups, the term almost always appears in connection with funding rounds. When a company raises 500 million dollars, the question usually follows of how long that money will last at its current burn. For AI companies, answers of one to two years are common. That explains why some companies keep raising new capital year after year.

Publicly traded corporations also publish the underlying data. The quarterly report shows free cash flow, meaning the cash inflow after investments. If it’s negative, the corporation is burning money. This happens even at very large companies when they are currently building data centers.

A typical misconception is the assumption that burning money means wasting it. The term only describes the direction of the cash flow. Amazon burned money for years and built a huge business out of it. Other companies used up their capital without results. The metric alone does not distinguish between these two cases.