Burn Rate & Runway Sensitivity Simulator
Model startup runway and burn rate with dynamic revenue/expense growth. Enter values for instant results with step-by-step formulas.
Worked Examples
Example 1: Pre-Revenue Startup Crisis
Problem: Startup has $800K cash, $0 revenue, burning $120K/month (15 people × $8K loaded cost). No revenue growth yet. How long until broke?
Solution: Current State:\nCash: $800,000\nMonthly revenue: $0\nMonthly expenses: $120,000\nMonthly burn: $120,000\n\nCurrent Runway:\n$800K / $120K = 6.67 months\n\nThis is CRITICAL territory.\n\nProjection (no revenue change):\nMonth 0: $800K\nMonth 1: $680K\nMonth 2: $560K\nMonth 3: $440K\nMonth 4: $320K\nMonth 5: $200K\nMonth 6: $80K\nMonth 7: -$40K (BROKE)\n\nOptions:\n\n1. Cut burn to extend runway:\n Cut 5 people: $40K/month savings\n New burn: $80K/month\n New runway: $800K / $80K = 10 months\n \n2. Raise emergency bridge:\n $500K bridge extends by 4 months\n Buys time to hit milestones\n \n3. Generate revenue quickly:\n Need $30K revenue ASAP to buy time\n Consulting, services, anything cash-positive\n \nRecommendation:\nCombination:\n- Cut burn by 25% ($30K/month)\n- Gen
Result: 6.7 months runway (CRITICAL) | Must cut burn OR raise OR generate revenue | Combination approach best
Example 2: Growth-Stage Burn Analysis
Problem: SaaS company: $5M cash, $400K MRR, $600K monthly expenses, 10% revenue growth, 8% expense growth. Analyze runway and break-even path.
Solution: Current State:\nCash: $5,000,000\nRevenue: $400,000/month\nExpenses: $600,000/month\nBurn: $200,000/month\n\nCurrent Runway:\n$5M / $200K = 25 months\n\nProjection with Growth:\n\nMonth 0:\nRev: $400K, Exp: $600K, Burn: $200K, Cash: $5M\n\nMonth 6:\nRev: $400K × 1.10^6 = $709K\nExp: $600K × 1.08^6 = $952K\nBurn: $243K\nCash: $5M - (cumulative burn) ≈ $3.7M\n\nMonth 12:\nRev: $400K × 1.10^12 = $1,256K\nExp: $600K × 1.08^12 = $1,509K\nBurn: $253K\nCash: $5M - (cumulative) ≈ $2.1M\n\nProblem: Burn is INCREASING!\nRevenue growing 10%\nExpenses growing 8%\nBut starting from higher base ($600K vs $400K)\n\nBreak-even analysis:\nRevenue needs to catch expenses.\nRevenue growing faster (10% vs 8%)\n\nMonth when Rev = Exp:\n$400K × 1.10^n = $600K × 1.08^n\n1.10^n / 1.08^n = 1.5\n(1.10/1.08)^n = 1.5
Result: 25 months runway | Break-even month 22 | Should reach profitability | Monitor trajectory
Example 3: Expense Cut Scenario Planning
Problem: Startup: $1.2M cash, $50K revenue, $180K burn. Board asks for scenarios: 10% expense cut, 20% cut, 30% cut. What's the impact?
Solution: Base Case:\nCash: $1,200,000\nRevenue: $50,000\nExpenses: $230,000 (revenue + burn)\nBurn: $180,000\nRunway: $1.2M / $180K = 6.67 months\n\nScenario Analysis:\n\n10% Expense Cut:\nExpenses: $230K × 0.90 = $207K\nBurn: $207K - $50K = $157K\nRunway: $1.2M / $157K = 7.64 months\nGain: +0.97 months\n\n20% Expense Cut:\nExpenses: $230K × 0.80 = $184K\nBurn: $184K - $50K = $134K\nRunway: $1.2M / $134K = 8.96 months\nGain: +2.29 months\n\n30% Expense Cut:\nExpenses: $230K × 0.70 = $161K\nBurn: $161K - $50K = $111K\nRunway: $1.2M / $111K = 10.81 months\nGain: +4.14 months\n\nImpact Summary:\n10% cut = +1 month runway\n20% cut = +2.3 months\n30% cut = +4.1 months\n\nNon-linear: Each cut has bigger marginal impact.\n\n30% Cut Details:\nLikely means:\n- Cut 6-7 people (out of ~15-20)\n- Eliminate con
Result: Base: 6.7 months | 20% cut: 9 months (+2.3) | 30% cut: 10.8 months (+4.1) | Non-linear impact
Frequently Asked Questions
What is burn rate?
Burn rate is how much cash a company spends monthly beyond what it earns. If revenue is $100K and expenses are $300K, burn rate is $200K/month. Startups track burn rate obsessively as it determines survival time.
What is runway?
Runway is how long a company can operate before running out of cash, calculated as Cash ÷ Monthly Burn. With $2M cash and $200K burn, runway is 10 months. It's the most critical startup survival metric.
How much runway should a startup have?
Rule of thumb: 12-18 months minimum. Less than 12 months means immediate fundraising. Less than 6 months is crisis mode. Raising new funding typically takes 3-6 months, so start when 9-12 months remain.
What's a healthy burn multiple?
Burn multiple = Net Burn ÷ Net New ARR. Under 1.5x is excellent (efficient growth). 1.5-3x is good. Above 3x is concerning—burning too much per dollar of growth. Top SaaS companies achieve <1.5x.
Should I reduce burn or increase revenue?
Depends on stage. Pre-product/market fit: burning for growth may be premature; find fit first. Post-PMF: burn to grow is justified if unit economics work. Always easier to cut costs than grow revenue quickly.
How do I extend runway without raising capital?
Options: cut discretionary expenses, reduce headcount, renegotiate vendor contracts, delay non-critical initiatives, increase prices, accelerate collections, or sell assets. Emergency measures include: founder salary cuts or bridge loans.