Cash runway estimates how many months your startup can operate before its cash is depleted at its current net burn rate. To use the figure well, calculate it with revenue included, update it regularly, and treat it as a planning estimate rather than a guarantee.
How do you calculate cash runway?
Use this formula:
Cash runway in months = cash available ÷ net monthly burn
Net monthly burn is the cash going out during a month minus the cash coming in. If you use total expenses instead of net burn, you ignore revenue that helps cover those expenses.
For example, a startup with $600,000 in the bank, $70,000 in monthly expenses, and $20,000 in monthly revenue has net monthly burn of $50,000. Dividing $600,000 by $50,000 gives the company 12 months of runway at that rate.
That result is a snapshot based on the inputs you use. It does not account for changes in revenue, spending, or the timing of future costs. Revisit the calculation as those inputs change, and compare each estimate with earlier ones to see whether the available time is increasing or shrinking.
What does cash runway tell you about your startup?
Runway estimates how long your current cash can support your company’s operations if its net burn continues. Burn rate, by contrast, describes the monthly pace of cash loss. One is a time horizon; the other is a rate.
For planning, the number becomes more useful when you understand what is behind it. Consider the cash balance, monthly costs, cash coming in, and any assumptions that could change. Hiring plans, shifts in revenue, or a large upcoming expense may mean the current calculation does not reflect what lies ahead.
The trend matters as well as the latest estimate. If runway is falling while revenue stays flat, review spending and fundraising plans before the remaining time becomes a constraint. Recalculate monthly, and update the assumptions when the business changes.
How much cash runway should a startup plan for?
A common planning target is 18 to 24 months of runway after raising. This gives you time to work toward milestones before needing additional capital. The right plan depends on your company’s cash position and expected spending, so treat these ranges as guardrails rather than a substitute for a company-specific plan:
- 18 months or more: There is room to work toward milestones and raise on a planned timeline.
- 12 to 18 months: Continue progress toward milestones while monitoring the runway trend.
- 6 to 12 months: Begin fundraising preparation. The process can take months.
- Under 6 months: Timing can become urgent, with fewer options and weaker negotiating leverage.
A raise typically takes 3 to 6 months. That is why founders should not wait until cash is almost gone to begin building an investor pipeline. A practical guardrail is to start actively fundraising at around 6 months of runway remaining. Starting earlier gives you more time to plan and manage the process.
How can you extend startup cash runway?
To extend runway, focus on decisions that reduce net burn or improve the timing of cash coming in. First, understand which costs have the largest effect. Payroll and marketing can be significant expenses, so review the spending that most affects the monthly cash outflow.
You may be able to delay hires, tools, or projects that are not essential to the next milestone. Prioritize cuts carefully: reducing burn matters, but spending tied to important company goals may need to continue.
Revenue and cash collection are other levers. Increasing revenue can lower net burn, while collecting receivables faster can improve the timing of cash coming in. Pricing changes may also be relevant. Grants or revenue-based financing may be options to consider, and a raise or bridge can add cash. Fundraising takes preparation and time, so include that timing in your plan.
What cash runway mistakes should founders avoid?
A few common calculation and planning errors can make runway less useful:
- Using total expenses as burn: Expenses alone do not account for revenue. Subtract monthly cash coming in from monthly cash going out to calculate net burn.
- Relying on one calculation: Cash, costs, and revenue can change. Update the estimate regularly.
- Ignoring the direction of travel: A declining runway alongside flat revenue is a reason to review the plan before the situation becomes urgent.
- Starting fundraising too late: If a raise takes 3 to 6 months, beginning with little time left can limit your room to manage delays.
- Cutting costs without priorities: Identify the largest expenses, then distinguish costs that support the next milestone from those that can wait.
The goal is not to treat one runway estimate as a prediction. Use it to guide decisions, make assumptions explicit, and revisit those assumptions as the company’s finances change.
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Frequently Asked Questions
Is cash runway the same as burn rate?
No. Burn rate measures the cash a company loses per month. Runway estimates how many months the available cash can last at that rate.
Should you include revenue when calculating runway?
Yes. Calculate net monthly burn by subtracting monthly cash coming in from monthly cash going out. This accounts for revenue that offsets spending.
When should you start raising money?
A practical guardrail is to start actively fundraising at around 6 months of runway remaining. A raise typically takes 3 to 6 months, so starting before cash becomes critical gives you more time to manage the process.
What is a common runway target after a raise?
A common planning target is 18 to 24 months after a raise. The amount of runway to plan for depends on your company’s cash, spending, and goals.
How often should you recalculate cash runway?
Recalculate it monthly and whenever important assumptions change. Compare the result with previous estimates to understand whether runway is shrinking or improving.