Burn Rate & Runway Calculator — Months of Cash Remaining

How it works

Net burn rate is monthly expenses minus monthly revenue — the actual cash being consumed. Runway is your cash balance divided by net burn. If revenue exceeds expenses you're cash-flow positive and runway is effectively unlimited. The calculator also estimates roughly when cash runs out at the current trajectory.

Common mistakes

• Using a single-month snapshot — January burn looks huge if you paid an annual SaaS bill that month. February looks great because the bill is gone. Neither number is real. Always use a 3-month rolling average and pull annual or one-off items into a separate line so the underlying trend is visible.
• Starting fundraising too late — fundraising takes 3–6 months in healthy markets and 9+ months in tight ones. Beginning conversations with under 6 months of runway forces accepting bad terms or bridge financing. The action threshold is 12 months of runway, not 6.
• Cutting growth before cutting waste — when runway is short, founders often slash marketing and sales first because they are the easiest line items to zero out. That kills future revenue and shortens runway further. Cut overlapping tools, premium office space, and underperforming hires before touching the growth engine.

When to use this calculator

Use this for the single founder/investor health metric — months of runway given current cash and net monthly burn. It is the right tool for board updates, investor decks, and any conversation that needs one number rather than a full forecast.

For a month-by-month forecast with seasonal lumps and tax dates, use the Cash Flow Calculator instead. To pressure-test what happens when revenue ramps fast enough to make burn negative, pair this with the Break-Even Calculator.

Worked example

A US seed-stage SaaS startup closes a $1.8M seed round. Monthly costs after hiring the planned team: six engineers at $12,000 fully-loaded (salary plus 25% benefits and payroll taxes) = $72,000. Founder cash compensation: $8,000. Cloud and third-party tools: $5,000. Office and operations: $3,000. Marketing and sales: $2,000. Gross burn rate = $90,000 per month. Revenue is currently $5,000 in monthly recurring revenue from early customers.

Net burn rate = $90,000 − $5,000 = $85,000 per month. Runway = $1.8M ÷ $85,000 ≈ 21 months. The fundraising rule of thumb is to begin a Series A process at 12–14 months of runway remaining (which gives roughly 6 months to close before falling below 6 months, the point at which negotiation leverage collapses). 21 months gives this team approximately 7–9 months to focus on growth before fundraising preparation becomes urgent.

The two levers that change the picture meaningfully are cutting cost or accelerating revenue. Reducing gross burn by 15% ($13,500 a month, perhaps by deferring two hires) extends runway to 25 months. Tripling MRR from $5k to $15k over the next six months drops net burn to $75,000 and pushes runway past 24 months. Investors expect MRR growth of 15–20% month- on-month at this stage, so the revenue lever is the one to obsess over — but cost cuts buy planning room while the growth motion is still being figured out.

Frequently Asked Questions

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Try these scenarios

Pre-filled examples — click any chip to load the inputs and result.

• Pre-revenue: $500k cash / $0 in / $50k out
• Early stage: $1M cash / $20k in / $80k out
• Approaching profit: $300k / $60k in / $70k out

How to calculate startup burn rate and runway

1. 1
   Enter current cash balanceBank balance plus liquid assets — the total you can spend.
2. 2
   Enter monthly revenueAverage monthly income. Use 0 for pre-revenue startups.
3. 3
   Enter monthly expensesTotal monthly cash outflows — salaries, rent, software, suppliers.
4. 4
   Read burn rate and runwayGross burn (total expenses), net burn (expenses minus revenue), and runway in months. The cash exhaustion date estimates when funds run out at current trajectory.