Startup
Startup Runway Calculator
Calculate months of runway from cash, burn rate, and revenue growth assumptions.
Result
Cash projection
How do you calculate startup runway?
Runway is cash on hand divided by monthly net burn, and net burn is monthly spend minus the revenue you collect. A startup with $300,000 in the bank, $30,000 of monthly spend and $6,000 of revenue burns $24,000 a month, so this calculator returns 12.5 months of runway, with cash running out in month 13.
Runway (months) = cash on hand ÷ (monthly spend − monthly revenue)
When revenue grows or spend falls, net burn changes every month, so the calculator steps forward month by month instead of using one division. It reports the fractional month in which cash hits zero and the first month revenue covers spend.
Runway examples, computed by this calculator
Same starting point in each row: $300,000 cash, $30,000 monthly spend, $6,000 monthly revenue.
| Scenario | Runway | Break-even month |
|---|---|---|
| Flat revenue | 12.5 months | not before cash runs out |
| Revenue +5% a month | 13.9 months | not before cash runs out |
| Revenue +10% a month | 120+ months | 18 |
| Flat revenue, spend cut 3% a month | 16.8 months | not before cash runs out |
Growth compounds: at 5% monthly growth runway stretches to 13.9 months, and at 10% the company breaks even in month 18 and never runs out. Set your decisions on the flat-revenue number, because growth is the input most likely to disappoint.
How much runway should a startup have?
Enough to reach the next raise or profitability, plus a buffer. For venture-backed startups the gap between rounds is long: Carta reported median waits of 774 days between seed and Series A for rounds in Q4 2024 and 616 days in Q2 2025, roughly 20 to 25 months, so 18 to 24 months after a raise is a sensible planning floor. Bootstrapped companies should plan runway to the break-even month instead. The startup runway planning guide covers trigger points and ways to extend runway.
Common runway calculation mistakes
- Using booked instead of collected revenue. Enter cash that actually arrives each month, not contract value.
- Dividing by gross burn only. Gross-burn runway (10 months here) is a stress test for revenue stopping, not the headline number.
- Forgetting lumpy payments. Annual renewals, taxes and hiring plans change the month cash runs out; add them to your monthly spend in the months they land.
- Planning on optimistic growth. Run a flat case and a downside case before acting on the growth case.
Related: the monthly burn rate calculator builds the spend figure line by line, the bootstrapped runway calculator adds personal living costs, and the employee cost calculator shows what one hire adds to monthly burn.
What does the Startup Runway Calculator calculate, and which formula does it use?
The Startup Runway Calculator projects how many months your cash lasts. Starting from cash on hand, it steps month by month: revenue compounds by your growth rate, burn shrinks by your reduction rate, and net burn (burn minus revenue) is drawn from cash each month. Runway counts the months the cash covers, including the fraction of the month in which it runs out; it also flags the break-even month when revenue overtakes burn.
Last updated .
How to use it
- Enter cash on hand, monthly burn, current monthly revenue, expected monthly revenue growth, and any planned burn reduction. Use fully loaded burn including payroll, software, rent, and debt service so runway reflects real cash usage.
- Read months of runway (including the part of the month in which cash runs out), the month cash runs out, the monthly cash projection, and break-even month. Fewer than 6 months of runway is usually acute, while 12-18 months gives most startups a healthier fundraising or restructuring window.
- Compare break-even month to cash-out month, not just to your optimism about growth. If break-even arrives after cash reaches zero, the current plan still fails even if the top-line narrative sounds attractive.
- Use the projection to test a no-growth case, a modest growth case, and a burn-cut case before making hiring or fundraising decisions. If a 10% burn reduction adds more runway than an aggressive growth assumption, the operations lever is probably safer than the sales story.
- Re-run monthly after the close and after any staffing, pricing, or financing change. Track actual runway versus modeled runway because even one or two bad months can pull the cash-out date forward sharply.
Questions people usually ask
What is the startup runway formula?
Runway in months equals cash on hand divided by monthly net burn. So a startup with $300,000 in the bank burning $50,000 a month has six months of runway. This calculator extends that base formula by letting you layer in monthly revenue growth and planned burn reduction, since both push the cash-out date further away.
How do I calculate my burn rate?
Net monthly burn is your total monthly operating costs minus monthly revenue: it's the cash actually leaving the business each month. If you spend $80,000 and bring in $30,000, your net burn is $50,000. In this calculator enter the $80,000 as monthly burn and the $30,000 as monthly revenue; it subtracts the revenue itself, then grows it and trims the burn month by month to return runway in months.
What is startup runway?
Runway is the number of months your startup can continue operating at its current burn rate before cash reaches zero.
How is revenue growth modelled?
Revenue compounds monthly at your specified growth rate. A 5% monthly growth means revenue multiplies by 1.05 each month.
What if my burn rate changes?
Use the burn reduction percentage to model decreasing costs over time. Set to 0% for constant burn.
Is this tool free and private to use?
Yes. AI Biz Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.
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Workflows that use this calculator
Background on the Startup Runway Calculator
- Formula Startup Runway Formula
Calculate your startup's financial survival time. Learn how to use Cash On Hand and Monthly Burn to predict runway, make strategic decisions, and secure.
- Formula Payback Period Formula
Understand the Payback Period Formula to quickly assess investment recovery, important for managing your startup's financial runway at AI Biz Hub.
- Formula Cash Conversion Cycle Formula (CCC) Explained
The cash conversion cycle formula is DIO + DSO - DPO. See each component, a worked example, and how to shorten the cycle to free up working capital.
- Examples Startup Runway Examples
reveal actionable insights into startup runway calculations. Learn how diverse factors like revenue growth, inventory, grant milestones, and strategic.
- Examples Payback Period Examples
Explore practical payback period examples across diverse industries. Master this vital metric to assess project viability, manage investment risk.
- Examples CAC Payback Examples
CAC payback examples across SaaS, e-commerce, and B2B: how long it takes to recoup acquisition cost at different gross margins and average order values.
Articles
- 8 min read Startup Runway: How Much You Need and How to Plan It
Startup runway is cash divided by monthly net burn. How much runway a startup should have, worked growth and burn-cut scenarios, and when to start raising.
- 11 min read Bootstrapped Runway vs Classical Runway: Two Methods Compared
Classical runway gives one number; bootstrapped gives five. On the same scenario, classical shows 0 months while bootstrapped shows 120 months.
- 12 min read How to Calculate Runway Under Revenue Volatility
Calculate runway under revenue volatility: fixed-burn calculators mislead. The honest method runs a monte-carlo on monthly cash flow ranges.
More in Bootstrapped growth
See when cash runs out, what you need to break even, and how to grow without funding.
- Monthly Burn Rate Calculator
- Break-Even Units Calculator
- Sales Forecast Calculator
- ROI + Payback Period Calculator
Use it from code
The same calculation as a JavaScript module you can import. It runs where you import it, with no request, key or rate limit.
import { compute } from "https://aibizhub.io/engines/startup-runway-calculator.js";Input and output contract, TypeScript types and the guide for agents.