Startup Cash Runway CalculatorFree online financial calculator — instant results, no sign-up
Estimate runway from available cash and constant monthly cash inflows and outflows.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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About the Startup Cash Runway Calculator
The Startup Cash Runway Calculator estimates how many months a startup's available cash can cover the gap between constant monthly cash outflows and inflows. It calculates monthly net cash burn, then divides available cash by that burn to estimate runway. Use it to assess your current cash cushion under a steady spending and collection scenario.
- Available cash ($)
- The cash currently available to fund business operations, measured in dollars, with a default of $450,000.
- Monthly cash outflows ($)
- The total cash expected to leave the business each month, measured in dollars per month, with a default of $60,000.
- Monthly cash inflows ($)
- The total cash expected to enter the business each month, measured in dollars per month, with a default of $25,000.
Formula and method
B = O − I; R = C / B, for B > 0. With the default inputs: B = $60,000 − $25,000 = $35,000.00 per month; R = $450,000 / $35,000 = 12.8571 months.
- CAvailable cash, in dollars.
- OConstant monthly cash outflows, in dollars per month.
- IConstant monthly cash inflows, in dollars per month.
- BMonthly net cash burn, in dollars per month; positive values mean cash is being depleted.
- REstimated runway, in months, when monthly net cash burn is positive.
Subtract monthly cash inflows from monthly cash outflows to find monthly net cash burn. If burn is positive, divide available cash by that amount to estimate the time until cash is exhausted. If burn is zero or negative, the model does not produce a finite cash-depletion runway because cash is stable or increasing.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Available cash450000 $
- Monthly cash outflows60000 $
- Monthly cash inflows25000 $
Results
- Monthly net cash burn$35,000.00
- Estimated runway12.8571
How to use the Startup Cash Runway Calculator
- 1Enter available cash, using $450,000 to reproduce the default example.
- 2Enter monthly cash outflows, using $60,000 for the default example.
- 3Enter monthly cash inflows, using $25,000 for the default example.
- 4Review monthly net cash burn: the default inputs produce $35,000.00.
- 5Review estimated runway: the default inputs produce 12.8571 months, then adjust the inputs to assess changes in spending or collections.
Reading your result
Monthly net cash burn shows how much cash the business loses each month after inflows offset outflows. The default result of $35,000.00 means cash declines by that amount each month. Estimated runway shows how long available cash lasts at that rate: 12.8571 months means approximately 12.86 months, not 12 months and 85 days. Zero burn indicates stable cash, while negative burn indicates cash accumulation; neither implies a finite depletion date under these assumptions.
Limitations
The estimate assumes constant monthly inflows and outflows and treats net burn as evenly spread over time. It does not model payment timing, seasonal changes, growth, unexpected expenses, or future financing unless reflected in the inputs. Include only cash that is actually accessible, and do not treat booked revenue as cash received or noncash accounting expenses as cash paid. The result estimates depletion to zero rather than to a minimum operating reserve, so practical fundraising or cost-reduction deadlines may arrive earlier.
Common questions
Why does the calculator use net cash burn rather than total monthly outflows?+
Monthly inflows offset part of the cash leaving the business. With $60,000 in outflows and $25,000 in inflows, only $35,000.00 must be funded from the $450,000 cash balance each month, giving 12.8571 months of runway.
What happens if monthly inflows equal or exceed monthly outflows?+
Equal inflows and outflows produce zero net burn, so dividing cash by burn does not yield a finite runway. Higher inflows produce negative burn, meaning cash grows under the model rather than running out; a negative quotient should not be interpreted as a negative runway.
Should I include a planned funding round in available cash?+
Do not include unreceived funding in current available cash. You can evaluate a separate scenario once funding is accessible, but this calculator cannot represent a future funding arrival date or determine whether cash will last until that date.
Can I use monthly revenue as monthly cash inflows?+
Use cash expected to be collected during the month, not simply revenue recognized or invoices issued. Delayed customer payments can reduce actual runway even when reported revenue is strong.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.