Startup Runway & Burn Rate Calculator: Zero Cash Date

Enter cash, monthly expenses and MRR to get your net burn, months of runway and the date you run out of cash.

Runway and burn rate: how to find your zero cash date

Runway is the number of months your cash covers your losses: cash ÷ net burn, where net burn is monthly spending minus recurring revenue (MRR). With no growth, $250,000 of cash and $17,000 of net burn last about 14.7 months; the tool refines this by simulating MRR growth month by month.

How the tool works

  • Gross burn = payroll + hosting + marketing + other spending, minus the simulated cut (in %).
  • Net burn = gross burn − MRR.
  • Simulation: each month, cash falls by that month’s net burn, then MRR grows by the rate entered. Runway is the number of the month in which cash reaches zero or below; the simulation stops at 60 months.
  • As soon as a month has zero or negative net burn with cash left, the tool shows “profitable” and the runway becomes unlimited.
  • Zero cash date = today + runway in months.

The tool’s bands: 18 months or more, healthy; 10 to 18, moderate; under 10, critical. These are rough guides, not a standard.

Example

$250,000 of cash, $20,000 MRR, $37,000 of spending, so $17,000 net burn. With no growth, cash is down to $12,000 in month 14 and goes negative in month 15: a 15-month runway. With 2% monthly growth it lasts 20 months. At 5% (the default), MRR reaches $37,713 in month 14 and overtakes spending with $123,260 left: the tool shows “profitable”. With no growth, a 20% spending cut ($29,600) stretches runway to 27 months.

Limits

  • Spending stays flat: hiring, cost increases and seasonality are not modelled.
  • Growth is a constant rate; churn is not deducted separately.
  • Fundraising, loans and payment delays are not included.

This calculator is about cash; the related SaaS simulators cover acquisition efficiency (Magic Number, CAC payback) and MRR trajectory (churn, NRR). It is an estimate, not a substitute for a cash plan prepared with your accountant.

Frequently Asked Questions

How do you calculate a startup’s runway?

Divide available cash by monthly net burn (spending minus recurring revenue). $250,000 of cash with $17,000 of net burn gives 14.7 months; the tool, which counts the month in which cash runs out, shows 15 months with no growth.

What is the difference between gross burn and net burn?

Gross burn is total monthly spending (payroll, hosting, marketing, other). Net burn subtracts monthly recurring revenue: $37,000 of spending and $20,000 of MRR make a net burn of $17,000 a month.

How many months of runway should a startup have?

The tool rates 18 months or more as healthy, 10 to 18 as moderate and under 10 as critical. These are rough guides: fundraising often takes several months, so it pays to start well before the zero cash date.

How does MRR growth change runway?

The tool grows MRR each month by the rate entered, which shrinks net burn over time. With $250,000 of cash, $20,000 MRR and $37,000 of spending, runway goes from 15 months with no growth to 20 months at 2% a month; at 5%, the company turns profitable in month 14.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.