About Burn Rate Calculator
Burn rate is the most important financial metric for any startup, early-stage business, or project running on investor or reserve capital. It tells you exactly how fast you are spending cash each month and, by extension, how long you can survive before needing more funding or reaching profitability. A company with $500,000 in cash that burns $50,000 per month has ten months of runway. If the burn rate rises to $75,000 per month, that runway shrinks to less than seven months. This calculator takes your starting cash, ending cash, and the number of months between them to compute both total cash burned and average monthly burn. It also reveals whether your spending is accelerating or slowing. Founders use burn rate to make hiring decisions, plan fundraising timelines, and communicate with investors. A rising burn rate is not always bad if it funds growth that will pay off, but it must be deliberate and tracked. This tool gives you the clarity to distinguish healthy investment from reckless spending and to act before cash becomes a crisis.
How It Works
The calculator subtracts your ending cash balance from your starting cash balance to find total cash burned over the period. It then divides that total by the number of months to get the average monthly burn rate. If your ending cash is higher than your starting cash, the burn rate is negative, which means you generated cash during the period rather than spending it. The result is usually expressed as a positive number when spending exceeds income and a negative number when income exceeds spending. For example, if cash dropped from $500,000 to $350,000 over six months, total burn is $150,000 and monthly burn is $25,000. This number is the foundation for runway calculations and cash planning. The calculator assumes the cash change is entirely due to operations and does not adjust for one-time financing rounds, large equipment purchases, or seasonal revenue swings unless you exclude them manually.
Formula & Calculation Logic
The formula has two parts. Total cash burned equals starting cash minus ending cash. Monthly burn rate equals total cash burned divided by the number of months. For a company that began with $500,000 and ended with $350,000 six months later, total burn is $150,000 and monthly burn is $25,000. If ending cash were $600,000, total burn would be negative $100,000 and monthly burn would be negative $16,667, indicating cash generation. The formula gives an average over the period, so it smooths out month-to-month fluctuations. For a more granular view, calculate each month's cash change individually and look for trends.
Step-by-Step Guide
- Step 1: Enter your starting cash balance at the beginning of the period.
- Step 2: Enter your ending cash balance at the end of the period.
- Step 3: Enter the number of months between the two balances.
- Step 4: Click calculate to see total cash burned and average monthly burn rate.
- Step 5: Compare the monthly burn against your remaining cash to estimate runway.
- Step 6: Repeat monthly to spot trends and adjust spending or fundraising plans.
Example Calculations
- Scenario 1: A startup with $500,000 starting cash and $350,000 ending cash over 6 months burns $150,000 total, or $25,000 per month.
- Scenario 2: A company with $1,000,000 starting cash and $700,000 ending cash over 9 months burns $300,000 total, or $33,333 per month.
- Scenario 3: A business with $200,000 starting cash and $250,000 ending cash over 6 months has a negative burn rate of $8,333 per month, meaning it generated cash.
Common Use Cases
- Track startup runway and plan fundraising rounds before cash runs low.
- Report monthly burn to investors and board members.
- Evaluate whether hiring or marketing spend is increasing burn too quickly.
- Compare burn rate against revenue growth to assess unit economics.
- Model how cost-cutting measures affect monthly cash consumption.
Pro Tips
- Calculate burn rate monthly, not quarterly, to catch problems early.
- Separate recurring operating burn from one-time capital expenses.
- Track net burn, which includes revenue, not just gross spending.
- Maintain at least 12 to 18 months of runway between fundraising rounds.
- Use burn rate alongside cash flow forecasts for realistic planning.
Common Mistakes to Avoid
- Confusing gross burn with net burn by ignoring revenue.
- Using a one-time expense month as a long-term average.
- Forgetting to account for accounts payable timing differences.
- Waiting too long to fundraise because burn looked fine last quarter.
- Assuming a negative burn rate is always good without understanding revenue quality.
Why Use This Tool?
- Know exactly how fast your business consumes cash.
- Plan fundraising with data instead of panic.
- Identify spending trends before they become existential risks.
- Communicate financial health clearly to stakeholders.