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.

行业预设模板Click to test scenario

当前账面可用现金余额 ($)Liquid reserves

每月现金营业收入 ($)

每月总运营支出 ($)Gross Burn

Monthly Revenue Growth

Monthly Expense Growth

One-Time Upcoming Expense

Occurs in Month

Additional Funding Cushion

Arrives in Month

预计现金存续期 (Runway)

已进入自循环盈利 (Default Alive)

收支平衡 / 实现盈利

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

预计资金告罄日期:Indefinite

月度净现金消耗额 (Net Burn):US$28,000/mo

月度净现金消耗额 (Net Burn)

US$28,000

Expenses − Revenue

月度总运营支出 (Gross Burn)

US$60,000

Total monthly outlays

当前账面可用现金余额 ($)

US$400,000

Liquid reserves balance

盈亏平衡状态

Monthly sales required to eliminate cash burn entirely: US$60,000/month

距离盈亏平衡所需月收入差额: +US$28,000/mo

Projected Cash Remaining

Based on trajectory

After 3 MonthsUS$318,251

After 6 MonthsUS$244,723

After 12 MonthsUS$135,113

未来 24 个月现金流趋势推演

结合复合增长率的月度现金消耗轨迹折线图。

现金余额

Zero Cash Threshold

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

假设情景敏感度分析 (What-If)

评估即时缩减支出、提振销售或注入过桥资金对企业生存周期的延长效果。

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.