Cash Flow & Runway
Operating cash, not MRR, decides whether you survive.
How many months you can operate at current burn before running out of cash. MRR pays bills, runway buys time. The two diverge most when you're growing fast (heavy upfront investment) or shrinking (collections lagging cancellations).
Formula
Runway (months) = Cash on Hand ÷ Monthly Net BurnWorked example
$600,000 cash, $50,000 net burn (after MRR collections) → Runway = 12 months.
Benchmark
Healthy runwayWhy it matters
Profitable on paper and out of cash is the most common way SaaS startups die. Annual plans bring forward cash but also lock in churn risk; expansion deals are great revenue but typically have collection delays. Watch runway weekly when below 12 months, monthly otherwise.
Common mistakes
- Treating MRR as cash — invoiced ≠ collected. Net 30 customers can stretch to net 60.
- Forgetting upcoming tax payments, sales-tax accruals, and one-off vendor commitments.
- Modeling runway on average burn rather than the trailing-3-month burn (which includes recent headcount hires).
Tracked in FlowMRR
Treasury → gross/net receipts and cumulative cashflow chart. Runway itself needs your bank balance, which FlowMRR doesn't hold.
