Should SaaS runway be calculated using ARR or MRR?

Runway must always be calculated on a monthly cash basis using MRR cash collections and real monthly cash outflows, not recognized GAAP revenue or annualized run-rate (ARR).

Subscription & Cloud•Recommended Target: 14–18 months

SaaS Runway Calculator

Software-as-a-Service businesses enjoy recurring revenue compounding, but high upfront customer acquisition costs and deferred revenue timing make cash flow management unique. Use this calculator to model your subscription burn and cash exhaustion date.

Industry Benchmark Guidance (14–18 months):Healthy SaaS companies targeting Series A or profitability typically target 14 to 18 months of runway. With net revenue retention (NRR) above 100%, growing subscription revenue gradually offsets fixed server and payroll costs, expanding runway organically month over month.

Profiluri PredefiniteClick to test scenario

Disponibilități Bănești Actuale ($)Liquid reserves

Venit Lunar Încasat ($)

Cheltuieli Lunare Totale ($)Gross Burn

Monthly Revenue Growth

Monthly Expense Growth

One-Time Upcoming Expense

Occurs in Month

Additional Funding Cushion

Arrives in Month

Runway Estimat

Profitabil și Sustenabil (Default Alive)

Sustenabil / Profitabil

You are generating positive net cash flow of $28,000/month. Your cash balance is growing.

Data Estimată de Epuizare a Fondurilor:Indefinite

Rata Lunară Netă de Consum (Net Burn):28.000 USD/mo

Rata Lunară Netă de Consum (Net Burn)

28.000 USD

Expenses − Revenue

Rata Lunară Brută de Consum (Gross Burn)

60.000 USD

Total monthly outlays

Disponibilități Bănești Actuale ($)

400.000 USD

Liquid reserves balance

Prag de Rentabilitate (Break-Even)

Monthly sales required to eliminate cash burn entirely: 60.000 USD/month

Deficit de Venit până la Pragul de Rentabilitate: +28.000 USD/mo

Projected Cash Remaining

Based on trajectory

After 3 Months318.251 USD

After 6 Months244.723 USD

After 12 Months135.113 USD

Traiectoria Lichidităților pe 24 de Luni

Evoluția soldului de numerar lună de lună, luând în considerare factorii de creștere.

Sold Numerar

Zero Cash Threshold

Hover or tap any month marker to inspect exact projected cash balance, revenue, and burn for that period.

Planificare Scenarii Ipoteze (What-If)

Află cum reducerea costurilor, creșterea vânzărilor sau o rundă punte îți prelungesc viabilitatea companiei.

Reduce expenses by 5%Sustainable

Save $3,000/mo (new expenses: $57,000/mo)

Runway:

SustainableSustainable / Infinite

Reduce expenses by 10%Sustainable

Save $6,000/mo (new expenses: $54,000/mo)

Runway:

SustainableSustainable / Infinite

Reduce expenses by 20%Sustainable

Save $12,000/mo (new expenses: $48,000/mo)

Runway:

SustainableSustainable / Infinite

Financial Calculation Methodology & Transparency

How the Runway Calculator Works: Mathematical Model & Assumptions

1. Static Cash Runway Formula

For businesses with steady revenue and predictable overhead, runway is determined by dividing liquid cash reserves by net monthly cash deficit:

Runway (months) = Available Cash ÷ Net Monthly Burn

2. Gross Burn vs. Net Burn

Gross Burn: Total cash disbursed each month (payroll, contractors, hosting, rent, utilities).
Net Burn: Gross monthly expenses minus total monthly cash revenue collections.
Break-Even: When Net Burn $\le$ $0$, cash runway is mathematically sustainable or infinite.

3. Dynamic Growth Projections & Interpolation

When revenue growth or expense inflation rates are enabled, the engine calculates month-by-month compound flows up to 60 months:

Ending Cash(m) = Beginning Cash(m) + Revenue(m) - Expenses(m)

Fractional Month = Beginning Cash(depletion) ÷ Monthly Net Burn

We linearly interpolate the exact day/fraction when cash reaches $0, avoiding arbitrary rounded whole months.

4. Client-Side Privacy Guarantee

Every financial computation executes exclusively inside your local browser runtime. No financial balances, revenue figures, or payroll numbers are sent to any remote server or database.

Primary Cost Drivers

Major Burn Drivers for SaaS Companies

Customer Acquisition Payback Period

Sales and marketing spend required to acquire a customer before subscription cash payback is completed (often 12–18 months).

Hosting & Scalable Infrastructure

Multi-tenant database clusters, cloud monitoring, and third-party communications APIs that grow alongside active user seats.

Customer Success & Support

Onboarding specialists and support engineers required to maintain low churn and high net revenue retention.

Actionable Levers

How to Extend SaaS Companies Runway

Shift Monthly Accounts to Annual Subscriptions

Encourage customer migration to annual prepaid billing by offering 2 months free; upfront cash collections immediately lengthen your runway.

Focus on Low-CAC Organic & Product-Led Growth

Double down on documentation SEO, viral referral loops, and freemium conversion rather than expensive Google/LinkedIn paid ads.

Tackle Gross Logo & Revenue Churn

Every retained customer saves the cash burn required to replace them. Implement proactive customer health scoring.

Worked Calculation: B2B Workflow Automation SaaS

Starting Cash$400,000

Monthly Cash Inflow$32,000

Monthly Cash Outflow$60,000

A SaaS with $400k cash, $32k MRR, and $60k operating expenses faces a net burn of $28,000/month. At static burn, runway is 14.3 months. With 6% month-over-month MRR growth against 2% expense expansion, the company hits cash-flow break-even in month 16 before running out of money.