Cash runway is how many months a company can keep operating before it runs out of money, based on its cash on hand and net burn rate. Formula: cash ÷ monthly net burn. $1,000,000 in the bank burning $100,000/month gives 10 months of runway.
What Is Cash Runway?
Cash Runway represents the amount of time a company can continue operating before it runs out of cash, based on its current cash reserves and burn rate. It’s like calculating how many more months your business can survive before needing additional funding or becoming profitable.
What’s Included in Cash Runway? 💼
Cash Components:
- Current cash balance
- Cash equivalents
- Short-term investments
- Available credit lines
- Committed funding
Burn Rate Components:
Operating Activities:
- Employee costs
- Rent and utilities
- Marketing expenses
- Other operating costs
Investing Activities:
- Planned capital expenditures
- Expected investment needs
Financing Activities:
- Debt payments
- Interest obligations
How to Calculate Cash Runway
The basic formula for Cash Runway is:
Cash Runway = (Cash + Cash Equivalents) ÷ Monthly Net BurnNet burn = costs − revenue
Example:
- Current Cash and Cash Equivalents: $1,000,000
- Monthly Net Burn: $100,000
Cash Runway = $1,000,000 ÷ $100,000 = 10 months
You can also cross-check your own numbers with our free cash runway calculator.
Gross Burn vs. Net Burn
Which burn figure you divide by changes the answer, so it pays to know the difference:
| Metric | Definition | Use it to |
|---|---|---|
| Gross burn | Total monthly cash out, ignoring revenue | See your true cost base and worst case |
| Net burn | Monthly costs minus revenue | Estimate real runway at current sales |
Worked contrast: a startup with $750,000 in the bank spends $80,000/month and earns $50,000/month.
Net runway = $750,000 ÷ ($80,000 − $50,000) = 25 monthsNet burn $30,000/mo
Gross runway = $750,000 ÷ $80,000 = 9.4 monthsIf revenue dropped to zero
Net burn shows the likely path; gross burn shows how quickly things unravel if revenue disappears. Investors usually look at both.
Why It Matters
Running out of cash is one of the most common reasons startups fail — CB Insights' analysis of startup post-mortems consistently ranks "ran out of cash / couldn't raise" near the top. Runway is the single number that tells you how much time you have to fix that. Understanding it is crucial for:
- Planning fundraising timing
- Making hiring decisions
- Managing growth rate
- Setting spending priorities
- Strategic planning
- Survival planning
Types of Runway Analysis
Conservative Runway:
- Uses gross burn rate
- Ignores potential revenue
- Most conservative estimate
Realistic Runway:
- Uses net burn rate
- Includes predictable revenue
- Most commonly used
Optimistic Runway:
- Includes potential revenue increases
- Considers cost optimizations
- Used for best-case scenarios
Managing Cash Runway
To extend your runway:
Reduce Burn Rate:
- Optimize operations
- Cut non-essential costs
- Delay expansion plans
- Negotiate better terms
Increase Cash:
- Accelerate revenue
- Collect receivables faster
- Seek additional funding
- Sell non-core assets
Pro Tip: A long-standing rule of thumb from investors like Fred Wilson and Sequoia is to keep roughly 18–24 months of runway — enough to hit your next milestone and still have time to raise, since a round itself can take six months to close. In slower funding markets, founders often target the higher end.
Cash Runway FAQ
How do you calculate cash runway?
Divide your available cash by your monthly net burn rate: Cash Runway = cash ÷ net burn. With $1,000,000 in cash and a $100,000 monthly net burn, your runway is 10 months. Net burn is monthly operating (plus investing and financing) costs minus monthly revenue.
What is a good cash runway?
Most startups aim for at least 12 months of runway, and 18–24 months during uncertain markets or before a fundraise. Less than 6 months is a danger zone — you should already be raising or cutting burn.
What is the difference between cash runway and burn rate?
Burn rate is how much cash you spend per month; cash runway is how long your remaining cash lasts at that burn. Runway = cash ÷ burn rate, so lowering burn or adding cash both extend the runway.
When should I start fundraising based on runway?
Work back from the day you'd run out. Raising typically takes about six months, so begin planning with 12 months left, actively engage investors around 9 months, and be in full raise mode by 6 months. Waiting until 3 months of runway remains puts you in a weak, emergency negotiating position.
