There's a quiet moment, usually late on a Sunday, when a founder opens the cash flow model and the whole company comes into focus: the balance in the bank, the pace of spending and the months left to build toward the next milestone. That single number, your runway, shapes nearly every decision you make between now and your next raise.

From an investor's seat, runway reads as a plan rather than a timer, and reading it well is what separates a confident raise from a scramble. This guide covers how to calculate your runway, how much you should carry by stage and when to start raising against it.

What Is Startup Runway?

Runway is the number of months your company can keep operating before the cash runs out if spending stays where it is today. Running out of capital is almost always the final cause of death for a startup, which is why the number draws so much investor attention. The deeper problems usually sit underneath it, especially weak product-market fit or unit economics that never worked, and poor timing can make both harder to fix.

We read runway as the budget a founder has to prove the next milestone, which changes how much of it counts as healthy. CRV is an early stage venture capital investor, and when we look at a founder's runway we are asking whether the months of cash left can buy a result that makes the next round obvious. Our guidance to seed founders puts it plainly: the job of seed capital is buying you time to prove customers actually want what you're building.

How to Calculate Your Startup Runway

The calculation takes about a minute once you have two numbers: how much cash is in the bank and how fast you are spending it. Where founders trip up is the inputs, especially which burn figure a partner will ask about and how much a single unusual month can distort the plan. Getting those inputs right is what separates a runway number you can plan against from one that surprises you.

The Runway Formula, With a Worked Example

Runway captures how fast a startup spends the equity capital it raised, and the whole calculation fits on one line:

Runway (months) = Cash on Hand ÷ Monthly Net Burn

A company with $600,000 in the bank losing $75,000 a month after revenue has eight months of runway. With $250,000 in the bank and $70,000 of monthly burn, a leaner startup has closer to three and a half months, a different Sunday night entirely.

Gross Burn vs. Net Burn, and Which Number to Quote Investors

Gross burn is your total monthly cash expenses with no revenue subtracted, while net burn is what's left after your revenue offsets some of that spend. For a pre-revenue company the two numbers are identical. Once you're bringing in cash, net burn becomes the number investors watch most closely because it shows how fast you are actually approaching zero. You should report both when you talk to a partner: gross burn reveals your cost structure and net burn shows your real cash trajectory. A company with $400,000 gross burn and $300,000 in revenue looks far healthier than one burning $150,000 with only $20,000 coming in, even though the second looks leaner on paper.

Why a Trailing Average Beats a Single Month

A single month's burn can mislead you, and planning against it is how founders get surprised. An annual insurance premium or a late-paying customer can distort a month enough to make burn look cleaner or worse than it is. A trailing three-month average of net burn, recomputed every month, gives a steadier planning number that stays current as the business changes. Three months at $210,000, $245,000 and $230,000 average to roughly $228,000, a figure you can actually build a plan around. When burn is climbing month over month, though, the average hides that acceleration, so weight the recent months more heavily and treat last month's new hires as the baseline.

How Much Runway Should a Startup Have by Stage

Our runway targets have climbed as the gap between funding rounds has widened, because a buffer that made sense three years ago now leaves too little room to reach the next result. Founders are stretching each raise into longer runways to cover that gap, so the old targets no longer reach the next round. The right number depends on your stage and how efficiently you spend, and a few benchmarks hold across the market:

• Pre seed and seed: A target of 18 to 24 months funds roughly a year of focused building before fundraising begins, and the range should buy a specific milestone rather than months on the clock.
• Series A and beyond: The old shorter targets no longer cover the interval between rounds, so that same range has hardened into the standard for later stage companies.
• The 2026 bar: Market conditions have pushed runway expectations toward the higher end across stages, and longer buffers are common now that founders raise larger rounds upfront.
• Efficiency over raw months: Two years of cash paired with inefficient burn means capital drains slowly without proportional return, so the discipline behind the burn counts as much as the length of the runway.

Across every stage, more months only help when the burn behind them is disciplined and pointed at a fundable result. A longer buffer that funds inefficiency is a bigger budget for the same problem.

Default Alive vs. Default Dead: How Investors Read Your Runway

Paul Graham's default alive or default dead test asks one question about any startup: if spending stays flat and revenue keeps growing at its recent pace, does the company reach profitability on the cash it already has? A company that clears that bar is default alive, and one that falls short is default dead. Founders can miss the shift into default dead while the company still looks busy, especially when a useful product has weak pull and hiring keeps climbing on the hope that growth will catch up.

We score net burn, runway and the burn multiple together to read whether new capital would fund acceleration or survival. The burn multiple itself, net burn divided by net new annual recurring revenue, ties your cash consumption to the growth it produces, and lower burn multiples generally read as more capital efficient. In the artificial intelligence (AI) era that bar tightened: AI startups earned a 38 percent valuation premium at Series A in 2025, so building with AI tools without showing sharper efficiency now reads as a weakness.

How to Extend Your Runway and Lower Burn

Every lever here buys months toward a milestone, so the test for each one is whether it moves you closer to the result your next round needs. We reach for them roughly in this order:

• Pull cash forward: Expand existing customers and lift average revenue per user to improve cash timing, and offer a two to three percent discount for paying upfront, which pulls cash forward more cheaply than raising and faster than debt.
• Cut non-essential spend first: Audit redundant software subscriptions and shift to lower-cost marketing channels before you touch the team, since companies routinely overspend here.
• Renegotiate vendor and payment terms: Ask service providers for better terms while runway is still comfortable, because that conversation gets harder once cash tightens.
• Pace hiring to milestones: Tie each hire to a proven milestone, since salaries are the largest line item for most startups and headcount that outruns growth is the hardest cost to explain later.
• Tap non-dilutive capital: Weigh venture debt carefully, since its covenants can endanger a cash-burning startup, and claim research and development (R&D) tax credits, which can offset payroll tax up to $500,000 a year with contemporaneous documentation.

The founders who extend runway well lean on revenue and spending discipline before touching payroll, since it is the hardest cost to add back once a plan tightens. Each choice is a decision about how many more months of proof you can afford to buy.

When to Start Raising Against Your Runway

Fundraising timing should come from the milestone plan and the cash plan together, and the same logic behind when to raise a Series A applies at every stage: start while you still have proof and room to choose. A few rules keep the timing on your side:

• Open the round early: The process should open with 12 to 18 months of runway left, well before cash drops under six months.
• Budget the raise itself: The raise consumes three to six months from first contact to close, and later stage rounds run longer, so that time has to come out of your runway before you begin.
• Size it to the milestone: A round should fund 18 to 24 months of post-close runway that carries you to the specific milestone unlocking your next raise.
• Protect your position: A founder who opens with a short runway invites more scrutiny and gives up room to negotiate, because the other side of the table can see the same clock you can.

Cash visibility does the most for you when runway still leaves room to choose. CRV led Mercury's Series A and participated in its Series B and C, and because any partner can commit CRV within 24 hours, founders we back have sidestepped the emergency raises a short runway forces.

Your Startup Runway Is a Growth Plan, Not a Countdown

Managed well, runway becomes a forward-looking decision about what you are going to prove and how much time you will give yourself to prove it. Your burn multiple ties the default alive question to raise timing: whether the cash on hand funds acceleration toward a milestone or only delays the reckoning. CRV led Vercel's Series A and backed the company through its B, C, D and E rounds, and the founders we have backed longest treat every month of runway as budget for a specific result rather than time on a clock.

If you're an early stage founder looking for a partner for your next round, reach out to us to see if we'd be a good fit.

Frequently Asked Questions About Startup Runways

What happens when a startup runs out of runway?

When the cash hits zero and no new capital arrives, a startup usually has to shut down. Running out of money is almost always the final cause of death, though the deeper problems tend to be weak product-market fit or broken unit economics. Founders who see the wall coming act well before zero, since raising with a tight runway puts them in a weaker position.

Is 18 months or 24 months of runway better?

In the current market, 24 months is the safer target. A runway of 12 to 18 months can push you into fundraising before you have hit a meaningful milestone, and with the interval between rounds stretching, shorter buffers leave little margin. Founders who close with 24 or more months of post-round runway usually keep more room to choose the right terms and the right partner.

What is a healthy burn rate for a startup?

A healthy burn rate produces proportional growth, which the burn multiple measures directly. Lower burn multiples generally read as more efficient, and investors increasingly benchmark AI-native software companies against tighter efficiency expectations. The number itself weighs less than whether your spending is buying the revenue growth your next round requires.

What is the difference between burn rate and runway?

Burn rate is how fast you spend cash each month, and runway is how many months of operation that spending leaves, so one measures speed and the other measures distance. You calculate runway by dividing cash on hand by monthly net burn, which means lowering your burn directly extends your runway.