One of the first financial questions founders learn to ask is simple: How much runway do we have?
The calculation itself appears straightforward. Take the cash available and divide it by the monthly cash burn. If a company has €600,000 in cash and is spending €100,000 more than it generates each month, it has approximately six months of runway.
But while the calculation is simple, the decision behind it is not.
Runway is often treated as a number that tells a founder how long the company can survive. In reality, it should tell you something more useful: how much time you have to make the next important decision.
A startup with twelve months of runway is not necessarily in a stronger position than one with six months. It depends on what the company needs to achieve during that period, how predictable its revenues are, how flexible its costs are, and how difficult it will be to obtain additional funding.
The same amount of cash can therefore represent very different levels of financial security for different businesses.
This is particularly important because startup expenses rarely remain constant. A company may decide to hire additional employees, increase marketing expenditure, invest in technology, enter a new market or accelerate product development. These decisions may be necessary to support growth, but they also change the rate at which cash is being consumed.
A six-month runway today can become a four-month runway surprisingly quickly.
This is why runway should not be viewed as a static figure. It is a moving measure that changes whenever the assumptions behind the business change.
The most obvious factor is revenue.
Founders often build financial plans around ambitious growth assumptions. If revenue grows as expected, the company may approach profitability while maintaining a relatively comfortable cash position. But if growth is slower than anticipated, the effect can be significant. Lower revenue means less cash coming in, while many of the company’s costs remain unchanged.
The result is not simply lower profitability. It is a faster reduction in available cash.
The opposite can also happen. Stronger-than-expected growth can create financial pressure. More customers may require more employees, additional infrastructure, higher working capital or greater investment in operations. A company can therefore experience cash pressure precisely because the business is performing well.
This is one of the reasons why runway should be considered together with the broader financial model rather than as an isolated metric.
Another important question is what the runway is supposed to finance.
A startup raising capital should not simply ask how many months of expenses the money will cover. It should ask what it expects to achieve before that capital runs out.
Perhaps the objective is to reach €1 million in annual recurring revenue. Perhaps it is to reach profitability. Perhaps it is to prove product-market fit, expand into another country or achieve a particular number of customers.
The amount of capital required should ultimately be connected to those milestones.
If a company needs eighteen months to reach the next meaningful milestone, raising enough money for only twelve months may create unnecessary pressure. On the other hand, raising substantially more capital than required may introduce other considerations, including dilution, capital allocation and the temptation to increase spending simply because the cash is available.
There is therefore no universal answer to the question of how much runway a startup should have.
Twelve months may be appropriate for one company. Eighteen months may be more sensible for another. A mature business with predictable cash generation may operate comfortably with much less apparent runway than an early-stage company whose revenues are highly uncertain.
The more useful question is not “How many months of runway should we have?”
It is:
“How much time do we need to reach the next important milestone, with enough margin to deal with the fact that reality may not follow the plan?”
That last part matters.
Financial planning should not assume that everything will happen according to the base case. Revenue may grow more slowly. Customer acquisition may cost more. A major customer may delay payment. A funding round may take longer than expected. Hiring may become more expensive. An unexpected investment may suddenly become necessary.
A strong financial model should therefore show what happens under different circumstances.
What if revenue is 20% below expectations?
What if expenses are 15% higher?
What if the next funding round is delayed by six months?
What if growth is significantly stronger than expected and additional investment is required?
These scenarios transform runway from a simple countdown into a decision-making tool.
Imagine a startup that believes it has twelve months of runway. Under its base assumptions, that may be true. But under a more conservative scenario, perhaps the runway falls to eight months. If management discovers this when only three months remain, the available options may be limited.
If the same information is visible six months earlier, the company has choices.
It can slow hiring, reduce discretionary expenditure, change its growth strategy, improve collections, renegotiate costs, raise capital earlier or reconsider the timing of an expansion.
That difference is important.
The value of financial planning is not predicting exactly what will happen. It is understanding what could happen early enough to do something about it.
Runway should therefore be monitored continuously, but not obsessively. The objective is not to update a number every day without changing any decisions. The objective is to understand how changes in the business affect the company’s financial position and how much flexibility remains.
For founders, this also changes the way cash should be viewed.
Cash is not simply a resource that allows a company to continue operating. It is also time. More cash can provide more time to reach a milestone, test a strategy, respond to unexpected events or negotiate from a stronger position.
But time has value only if it is used deliberately.
A company with twelve months of runway and no clear plan for what needs to happen during those twelve months may be in a weaker position than a company with eight months of runway and a clear path toward its next milestone.
Ultimately, there is no magic number of months that defines a healthy startup.
The right level of runway depends on the business model, the predictability of revenues, the flexibility of costs, the company’s objectives, its access to capital and the uncertainty surrounding its next stage of growth.
What matters is not simply knowing how long the cash will last.
It is knowing what needs to happen before it runs out, what could prevent it from happening, and what decisions you can make today to preserve your options tomorrow.
For a startup, that is what financial planning should provide: not certainty, but visibility.
And in an environment where funding can take longer, growth can be less predictable and mistakes can become increasingly expensive, having that visibility may be one of the most valuable forms of runway a founder can have.
