SaaS Runway Calculator
Months of cash left — accounting for MRR growth and gross-margin contribution. Know your fundraise window before the board meeting.
Total monthly spend before any revenue offset.
Set to 0 for worst-case static-MRR runway.
Static runway
9.0 mo
Net burn $133,200/mo at today's MRR
With MRR growth
11 mo
Cash-out ≈ Apr 2027
Conservative
7.7 mo
Realistic
11 mo
Aggressive
13 mo
Bands swing on churn shocks, hiring pulls forward, and any non-recurring revenue collapsing.
Net burn is dominated by spend, not revenue. A 15% burn cut extends runway more than doubling MRR growth from 4% to 8% in the next 6 months.
Runway sits in the typical 9–18 month band — start serious fundraise conversations 6 months before zero.
- Gross-margin contribution = MRR × gross margin %
- Net burn = gross burn − gross-margin contribution
- Static runway = cash ÷ net burn
- Dynamic runway: simulate month-by-month with MRR × (1 + growth%) compounding
Common questions
What's the right runway threshold?▾
12 months is the 'start raising' line. 18+ months means you negotiate from strength. Under 6 months is bridge-or-die territory — cut burn or sign the next term sheet this quarter.
Gross burn vs net burn — which matters?▾
Net burn (gross spend minus gross-margin revenue) is what extends runway. But always know your gross burn too — if MRR drops 20%, net burn collapses toward gross burn fast.
Should I model MRR growth?▾
Yes. A 5% MoM grower with 12 months of static-MRR runway actually has 16–20 months of real runway. Conversely, a flat or shrinking MRR shortens runway faster than the linear calc suggests.
Why does gross margin show up here?▾
Because the dollar of revenue that extends runway is the gross-margin dollar, not the top-line dollar. 50%-margin SaaS extends runway half as fast as 80%-margin at the same MRR.