Why the business cash runway calculator matters
Runway is the only business metric that has a hard floor, and the useful version subtracts the reserve you would never actually spend before counting the months. This page turns that decision into a handful of inputs you can defend in a budget review: volume, unit cost, rate of adoption, and time. The output is a planning baseline, not a promise — it tells you whether the idea deserves a vendor quote, a pilot, or a pass.
- • Biggest swing factor: net burn, which you control faster than revenue
- • Second-order factor: the untouchable reserve, which shortens real runway
- • Often ignored: timing of receivables, which can swing a month either way
What actually changes the answer
net burn, which you control faster than revenue moves this number first, then the untouchable reserve, which shortens real runway. Run a conservative case and an upside case before you commit. If the maths only works in the upside case, treat it as a time-boxed test with a kill date rather than a line in next year's plan.
What to do with the result
If runway is under six months, model a 20% cost cut today rather than waiting — cuts take a month to show up in cash.
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Read the guideFAQ
What does the business cash runway calculator work out?
It applies Required units = ceil(demand × (1 + buffer%) ÷ output per unit); Cost = required units × cost per unit to the values you enter for cash in the bank ($), net monthly burn ($), cost of one more month of operation ($), reserve you refuse to spend. Runway is the only business metric that has a hard floor, and the useful version subtracts the reserve you would never actually spend before counting the months.
How accurate is this business cash runway calculator?
Straight-line runway. Seasonal revenue, tax payments and annual renewals can compress it faster than the average suggests. Replace the defaults with your own invoice, usage export, payroll data, statement, or vendor quote before making a commitment — the maths is exact, so the answer is only as good as the inputs you feed it.
Which input should I stress-test first?
net burn, which you control faster than revenue. Re-run with a pessimistic value for it; if the decision flips, that assumption is the thing you need real data on before signing anything. After that, check the untouchable reserve, which shortens real runway and timing of receivables, which can swing a month either way.
Which scenario should I start from?
Start with the preset closest to your situation — quiet period, normal load, peak load — then edit the sliders. Presets are realistic starting points, not benchmarks to match, and every change updates the result instantly.
What should I do after running the numbers?
If runway is under six months, model a 20% cost cut today rather than waiting — cuts take a month to show up in cash. A useful planning benchmark to compare against: Under six months of runway is the point most operators start cutting; under three is an emergency.
Can I share or save this calculation?
Yes. Your inputs are written into the page URL, so copying the link shares the exact scenario you are looking at — the person who opens it sees the same numbers. You can also export the inputs and results to CSV or PDF from the result card and keep it with the rest of your workings.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.