What is the Cash Burn Ratio Calculator?
The Cash Burn Ratio Calculator measures how many months a startup can continue operating before exhausting its cash reserves. It divides the current cash balance by the monthly net burn rate. This metric, also called runway multiple, is the single most important cash health indicator for early-stage and growth-stage companies.
How does it work?
Enter your current cash balance including all bank accounts and liquid investments. Enter your monthly net burn rate the amount by which expenses exceed revenue each month. The calculator divides cash by burn to show how many months of operations remain at the current spending level.
Formula
cash balance / monthly burn
How the calculation works
How the calculation works
- 1Enter your cash balance across all accounts.
- 2Enter your monthly net burn.
- 3Divide cash by monthly burn.
- 4The result is the number of months of operations your cash supports.
Worked example
Worked Example
A fictional Series A startup called FormFlow has $750,000 in the bank and is burning $63,000 per month net of revenue; the board wants to know how long it can operate.
- 1Cash burn ratio = $750,000 / $63,000 = 11.9 months.
- 2At current burn, cash runs out in about 12 months.
- 3A burn cut to $50,000 would extend the ratio to 15 months.
- 4FormFlow should begin a raise roughly 6 months before cash exhaustion.
Result
FormFlow has 11.9 months of runway, putting it in the 12-18 month range where raising soon is prudent.
Interpretation guide
How to read your result
Cash will run out within two quarters; every decision is now reactive and fundraising leverage is minimal.
Immediately cut non-essential spend and open fundraising conversations this month, not next quarter.
Enough time to operate but not enough to comfortably reach the next milestone without new capital.
Start the next round process now, and prepare a plan to extend runway if the raise slips.
The generally recommended planning window; you can operate while pursuing growth milestones.
Track the ratio monthly and define the trigger point that forces a raise or a cost cut.
Strong cash position relative to spend, giving you negotiating power and time.
Use the buffer to invest in growth, but avoid the trap of letting burn creep up without evidence of efficiency.
Benchmarks
Cash burn ratio (months of runway) guidance for startups
| Metric | Typical | Strong |
|---|---|---|
| Cash burn ratio (seed stage) | 9-15 months | 15-18 months |
| Cash burn ratio (Series A) | 12-18 months | 18+ months |
| Cash burn ratio (growth stage) | 12-24 months | 18-24 months |
| Investor red flag zone | Under 6 months | 6-12 months |
Common mistakes
- - Using gross burn instead of net burn, which understates the cash consumption rate
- - Assuming burn rate stays constant when it often increases with headcount growth
- - Not maintaining a minimum cash buffer for unexpected expenses or market changes
Practical tips
Practical tips
Use net burn, not gross burn, so revenue improvements show up in a healthier ratio.
Track the ratio monthly and treat a trend below 12 months as the trigger to start fundraising conversations.
Model the ratio under a 20% higher burn scenario so a hiring wave or delayed revenue does not surprise you.
Keep a separate reserve for one-time costs like legal fees, equipment, and severance that are not in monthly burn.
Recalculate immediately after any pricing, hiring, or cost-cutting decision rather than waiting for month end.
When should you use it?
- - Monthly cash health reviews with the executive team
- - Determining the urgency and timing of the next fundraising round
- - Evaluating the impact of cost-cutting measures on financial runway
- - Reporting cash position and projections to the board of directors
Benefits
- - Provides a clear timeline for critical financial decisions
- - Helps prevent the most common cause of startup failure running out of cash
- - Enables data-driven conversations about spending discipline and growth trade-offs
Use cases
- - Cash management and treasury planning
- - Fundraising timeline determination
- - Board reporting and investor updates
Step-by-step example
Total all cash held in checking, savings, and money market accounts. Calculate monthly net burn by subtracting revenue from total monthly expenses. Divide cash balance by monthly burn to determine how many months the company can operate. Track this number monthly and flag any downward trend.
Real-world example
A startup with $750,000 in the bank and a monthly net burn of $63,000 has a cash burn ratio of approximately 11.9 months. If the team reduces burn to $50,000 per month, the ratio extends to 15 months, providing more time to reach profitability or secure the next funding round.