Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Growth-adjusted runway (months)
15
Static (flat-burn) runway (months)
12.5
Month you reach cash-flow positive
0
Extra runway from growth vs static estimate
2.5
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How to use this
- 1Enter cash on hand ($).
- 2Enter current monthly revenue ($).
- 3Enter current total monthly costs ($).
- 4Enter monthly revenue growth rate (%).
- 5Enter monthly cost growth rate (%).
- 6Read your growth-adjusted runway (months) on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
A static runway calculation (cash divided by current monthly burn) understates real runway for a growing SaaS company because it assumes burn stays flat forever, when in reality revenue growth typically shrinks net burn month over month as the top line scales faster than costs. This calculator models month-by-month burn that declines as revenue grows at your assumed rate, giving a more realistic (and usually longer) runway estimate than the naive divide-by-current-burn approach most spreadsheets default to. That said, don't over-trust this model either — it assumes costs stay disciplined while revenue compounds smoothly, and real companies hit step-function cost increases (new hires, new infrastructure tiers, office leases) that a smooth growth-rate model won't capture. Use this as a best-case planning scenario alongside a flat-burn worst-case scenario, and raise money before you're inside 6 months of runway under the worst case, since fundraising itself takes 3-6 months and you don't want to be negotiating from a position of desperation.
Worked example
Using the values the calculator loads with:
Inputs
- Cash on hand: 3000000 $
- Current monthly revenue: 180000 $
- Current total monthly costs: 420000 $
- Monthly revenue growth rate: 5 %
- Monthly cost growth rate: 1.5 %
Results
- Growth-adjusted runway (months): 15
- Static (flat-burn) runway (months): 12.5
- Month you reach cash-flow positive: 0
- Extra runway from growth vs static estimate: 2.5
What each field means
Inputs
- Cash on hand ($)
- The cash on hand used in the calculation, measured in $. Starts at 3000000 $ so you have a working example on load.
- Current monthly revenue ($)
- The current monthly revenue used in the calculation, measured in $. Starts at 180000 $ so you have a working example on load.
- Current total monthly costs ($)
- The current total monthly costs used in the calculation, measured in $. Starts at 420000 $ so you have a working example on load.
- Monthly revenue growth rate (%)
- The monthly revenue growth rate used in the calculation, measured in %. Starts at 5 % so you have a working example on load. Accepted range: -20–50 %.
- Monthly cost growth rate (%)
- The monthly cost growth rate used in the calculation, measured in %. Starts at 1.5 % so you have a working example on load. Accepted range: -10–30 %.
Results
- Growth-adjusted runway (months)
- Returned as a length of time and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Static (flat-burn) runway (months)
- Returned as a length of time. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Month you reach cash-flow positive
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Extra runway from growth vs static estimate
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why is growth-adjusted runway usually longer than static runway?
Because static runway assumes today's burn rate continues unchanged forever, while in reality growing revenue closes the gap between costs and revenue every month, reducing net burn over time — sometimes to zero, at which point you stop burning cash entirely and runway becomes effectively infinite.
What growth rate assumption should I use?
Use your trailing 3-6 month average monthly growth rate, not your best month or an aspirational target. Overly optimistic growth assumptions in a runway model are dangerous precisely because they tell you that you have more time than you actually do.
Should I model a downside scenario too?
Yes, always run this alongside a flat or even declining revenue growth scenario. Boards and investors specifically want to see a downside case, and it protects you from discovering too late that your 'runway' assumed growth that didn't materialize.
When should I start fundraising relative to runway?
Start the process with 9-12 months of runway remaining under your conservative case, since raising typically takes 3-6 months end to end and you want negotiating leverage, not a cash-out-in-two-months story that forces you into a bad deal.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Cash Runway with Growth Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/saas-cash-runway-growth
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/saas-cash-runway-growth" target="_blank" rel="noopener">Cash Runway with Growth Calculator — RevenueLab</a> (2026).</p>
Source: [Cash Runway with Growth Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/saas-cash-runway-growth) (2026).