What burn rate is (gross burn vs net burn)
Burn rate is a cash planning metric that answers a simple question: how quickly are you spending money? It is most often used by startups and fast-growing businesses, but it is also useful for any company with a cash cushion and an operating plan that can change quickly.
Gross burn is the average amount of cash you spend each month (expenses). It is a view of your cost structure. Even if revenue is growing, gross burn is useful because it highlights the spending baseline you have committed to.
Net burn is gross burn minus revenue. Net burn is the true cash loss each month (or cash gain if negative). This is the number used to calculate runway because it determines how quickly your cash balance declines.
How runway is calculated
Runway estimates how many months you can operate before cash reaches zero, assuming your net burn remains the same. The common formula is runway = cash balance ÷ net burn. If net burn is zero or negative (meaning you are break-even or cash-flow positive), runway is effectively unlimited.
Runway is not a guarantee. Expenses can spike, revenue can dip, and timing matters (invoices, annual renewals, taxes). Still, runway is one of the most practical metrics for planning because it forces clarity about cash.
Why averaging multiple months improves accuracy
A single month can be misleading. Many businesses have uneven cash flows: annual software renewals, one-time contractor invoices, equipment purchases, or seasonal revenue patterns. By averaging multiple months of revenue and expenses, you reduce noise and get a clearer signal.
This calculator includes a multi-month table specifically for this reason. If you want a quick estimate, you can disable the table and enter a single month. For better planning, use 3–6 months (or more) and revisit the numbers after major changes like hiring or pricing updates.
How to use burn rate to make decisions
Burn rate is a decision tool. If runway is short, you may need to cut discretionary spend, pause hiring, renegotiate costs, or focus on revenue collection. If runway is long, you may have room to invest in growth initiatives, product development, or expanding channels — but you still want to track whether the investment improves unit economics.
Burn rate also helps align teams. When everyone understands the runway, it becomes easier to prioritize projects and avoid spending that does not move the business forward.
Frequently Asked Questions
What is burn rate?
Burn rate is the speed at which a company spends cash over time. It is commonly measured per month, especially for startups. Burn rate is used to understand how quickly cash reserves decline and how long the business can operate before it needs to raise money, cut costs, or reach profitability.
What is the difference between gross burn and net burn?
Gross burn is total cash outflow (expenses) per month. Net burn is expenses minus revenue (net cash loss) per month. A company can have high gross burn but low net burn if revenue offsets expenses. Net burn is what matters for runway calculations because it reflects how quickly the cash balance is shrinking.
How do you calculate runway?
Runway is the number of months you can operate before running out of cash, assuming net burn stays constant. A common formula is runway = cash balance ÷ net burn. If net burn is zero or negative (meaning you are break-even or cash-flow positive), runway is effectively unlimited.
Why should I average multiple months of data?
Burn rate can be noisy due to one-time expenses (annual insurance, equipment purchases) and seasonality in revenue. Averaging multiple months smooths the signal so you can make better decisions. This calculator lets you enter several months so the burn rate reflects a more representative period.
What is burn multiple?
Burn multiple is a common growth efficiency metric that compares net burn to revenue (or incremental revenue). In its simplest form here, burn multiple = net burn ÷ revenue. Lower is better. A high burn multiple means you are spending a lot of cash relative to revenue generation.
Should runway include future hiring plans?
Ideally yes. Runway is most useful when it reflects forward-looking plans. If you expect expenses to increase due to hiring or marketing scale, model those higher expenses in the upcoming months and recalculate. If you expect revenue growth, model that too to see how net burn changes.