Startup runway tells a company how long it can stay alive before its cash runs out. It is one of the most basic numbers a founder needs to know.
A startup may have a great product, strong sales, and a large market. But if the company spends cash faster than it brings cash in, it can still face a serious cash problem.
Runway gives founders a simple answer to a very important question: How many months can the business survive with the cash it has today?
The basic formula is simple:
Runway in months = Cash available ÷ Monthly net burn
For example, if a startup has $900,000 in cash and loses $75,000 each month, its runway is 12 months.
That means the company has about one year of cash left if its costs and cash income stay at the same level.
This basic method is useful, but it does not tell the full story. A startup may hire new staff, increase sales, cut costs, sign new customers, pay a large tax bill, or raise more capital. All of these events can change the runway.
What Does Cash Burn Mean?
Cash burn is the amount of cash a startup loses over a set period. Most founders look at burn on a monthly basis.
There are two useful numbers: gross burn and net burn.
Gross burn is the total cash a company spends each month. This can include salaries, office costs, software, marketing, contractors, insurance, legal fees, and other business costs.
Net burn also takes cash revenue into account.
For example, suppose a startup spends $160,000 each month and receives $40,000 in cash revenue. Its net burn is $120,000.
If the company has $1.2 million in cash, the simple runway calculation is:
$1.2 million ÷ $120,000 = 10 months
This means the startup has about 10 months of runway under its current cash pattern.
Why the Simple Runway Formula Can Mislead
The standard runway formula assumes that the future will look much like the present. That is often not true for a startup.
A young company can see large changes in both costs and revenue. A founder may plan to hire five people next month. A sales team may have several large deals close. A major customer may leave. A new product may increase revenue. A tax payment may create a large one-time cash outflow.
For this reason, a founder should not rely only on the current monthly burn.
A better approach is to calculate both current runway and forward runway.
Current runway uses the latest cash and burn figures. Forward runway uses expected future costs and revenue.
The second number can be more useful because it shows what may happen after the company takes its next steps.
A Simple Startup Runway Example
Consider a startup with $1.2 million in cash.
Its monthly expenses are $160,000, while monthly cash revenue is $40,000.
Its net burn is therefore $120,000.
At that rate, its current runway is 10 months.
Now suppose the company plans to hire several employees. Monthly expenses may rise to $190,000, while revenue stays at $40,000.
The new net burn becomes $150,000.
The forward runway is then:
$1.2 million ÷ $150,000 = 8 months
The company did not lose any cash when it made the hiring plan. However, the expected burn changed the future runway from 10 months to 8 months.
This is why a good runway calculator should let founders test future plans before they make them.
Why Runway Matters More in 2026
The fundraising market has changed in recent years. Startups can no longer assume that a new funding round will arrive soon after they start the process.
Carta data shows that the time between funding rounds has become much longer than the old 12-to-18-month model. For startups that raised a Series A in the fourth quarter of 2024, Carta reported a median gap of 774 days between primary rounds. That is about 2.1 years.
Carta has therefore pointed to a need for founders to plan for a longer period, with 24 to 30 months often used as a useful planning horizon.
CRV has also suggested an 18-to-24-month runway target for startups, based on the longer time that many companies may need before the next major financing event.
These figures do not mean every startup needs the same amount of cash. A company with strong revenue may need less outside capital than a company with little or no revenue. A company with a very predictable sales model may also have a different cash plan from a company with uncertain sales.
The key point is that fundraising can take time, so founders need to plan before the cash balance becomes too low.
Less Than 12 Months of Runway
The amount of runway left can also show how much pressure a startup may face.
Pilot’s 2026 Capital Efficiency Index found that the share of unprofitable VC-backed companies with less than 12 months of runway rose from 41% in June 2024 to 47% in June 2026.
That does not mean every company with less than 12 months of runway is in trouble. Some companies can raise capital quickly. Others may have strong sales growth or a clear path to profit.
Still, a shorter runway leaves less room for error.
A founder with 24 months of cash has more time to test a product, improve sales, cut costs, or prepare for a funding round. A founder with four months of cash has far less time to make those choices.
The 2026 Venture Capital Picture
The venture capital market in 2026 has both strong and difficult parts.
Carta reported $30.4 billion in startup funding in the first quarter of 2026. More than 60% of the capital on its platform went to AI companies.
This shows that large amounts of venture capital are still available. However, that capital is not spread evenly across all startups.
SVB’s H2 2026 State of the Markets report described a market with record highs in some areas, such as venture investment and valuations, while many startups still face a difficult fundraising environment.
SVB also estimated that 2,345 VC-backed companies were on pace to fail in 2026. It described this as the highest level in its historical series.
These figures show why runway matters. A startup cannot assume that a funding market with large total investment will automatically provide easy access to capital for every company.
Build Three Runway Numbers
A useful startup runway calculator should show more than one result.
The first number should be current runway. This uses the current cash balance and current net burn.
The second number should be forward runway. This uses expected costs and revenue after planned changes.
The third number can be called fundraising runway. This asks whether the company has enough cash to reach its next expected funding event.
For example, a startup may have 10 months of current runway but only 8 months of forward runway after planned hiring.
If the company expects its next funding round to take 12 months to reach, there is a clear gap between its cash plan and its financing plan.
That gap matters more than the simple 10-month number.
Use Different Scenarios
A strong runway calculator should also allow founders to test several future cases.
A base case can use the current plan for costs and revenue.
A growth case can assume higher revenue and higher costs from sales, staff, or product expansion.
A cost-cut case can show what happens if the company reduces discretionary spending.
A fundraising case can add new capital at a chosen future date.
A downside case can assume lower revenue or higher costs.
This approach gives the founder a range rather than one fixed number.
For example, a company may have 10 months of runway under its current plan, 14 months after a cost cut, and only 7 months under a downside case.
Those numbers give the management team a clearer view of its cash position.
Cash in the Bank Is Not the Whole Story
A startup may have $2 million in its bank account, but that does not always mean it has $2 million that it can freely use.
Some cash may be set aside for taxes. Some may support a specific business need. Some may need to cover known short-term obligations.
A more useful view is effective available cash.
This can include cash in the bank, highly reliable receivables, committed financing, and reasonably certain refunds or tax credits. It can then subtract restricted cash and unavoidable near-term obligations.
Founders should be careful with this calculation.
Unsigned sales deals are not cash. A possible investment is not cash. A sales pipeline is not cash. A customer promise without payment is not the same as money in the bank.
A runway model becomes much more useful when it uses realistic cash assumptions.
Runway and Profitability
Runway is closely linked to profitability, but the two numbers are not the same.
A company can have a long runway while it still loses money. It can also have a short runway while revenue grows quickly.
Pilot’s 2026 Capital Efficiency Index reported a median time to profitability of 4.2 years among the startups in its dataset. It also found that 20% were already profitable and another 18% were close to profitability.
These numbers show why founders should look beyond the cash depletion date.
A startup should ask what business milestone it can reach before the cash runs out.
That milestone may be profitability, positive cash flow, a major customer contract, product-market fit, a new funding round, or another clear business target.
What Runway Should a Startup Have?
There is no single runway number that works for every startup.
Still, current 2026 market guidance points toward longer planning periods than the older 12-to-18-month model.
An 18-to-24-month period is often used as a target after a funding round. Carta has also suggested planning for 24 to 30 months in some cases because the time between rounds can be much longer than before.
A startup with 12 to 18 months of cash has a meaningful planning window, but it may still need to prepare for its next financing event.
A company with 6 to 12 months of runway has less room for delays.
A company with less than 6 months of runway needs close attention to cash, costs, revenue, and financing options.
These are planning ranges, not universal rules. Each startup has a different business model, cost base, growth rate, revenue profile, and access to capital.
The Best Question Is Not Just “How Many Months?”
The most useful runway question is not simply, “When will our cash reach zero?”
A better question is, “What can we achieve before our cash reaches zero?”
This changes how founders use the number.
If a company has 15 months of runway, it should know what it expects to achieve during those 15 months. If it needs a funding round before month 15, the team should know how much time it needs to prepare.
If a company has eight months of runway, it may need a different plan from a company with 24 months.
The number itself is only the start. The real value comes from the decisions that follow it.
Final Thoughts
A startup runway calculator is simple at its core.
Cash ÷ net monthly burn = runway.
But a modern startup needs more than this basic formula.
The stronger approach adds future revenue, planned costs, fundraising time, one-time expenses, and downside cases. It also separates current runway from forward runway.
The 2026 data makes this even more important. Carta’s funding data shows longer gaps between rounds, while Pilot’s research shows that a large share of unprofitable VC-backed companies have less than 12 months of runway. At the same time, Carta reported $30.4 billion in startup funding in Q1 2026, with more than 60% of its platform capital going to AI companies.
The message from these figures is not that every startup needs the same amount of cash. It is that founders need a clear view of their own cash position.
Know the cash balance. Know the net burn. Know the future burn. Know the funding timeline. Then test what happens if revenue is lower or costs are higher.
A runway number is useful on its own. A runway model is much more useful because it helps a startup see what may happen next.
Also Read – AI Startup Ideas for 2026: Problems Businesses Will Pay For