Startup Runway Calculator

Startup runway = months before cash runs out at current burn. Critical metric for founders and investors. This calculator shows either runway months or months to break-even if revenue grows.

500k cash, 40k monthly burn, 10k monthly revenue growing 15% monthly: revenue hits burn at month 9, profitable. Without growth (flat 10k revenue): 16 months runway.

Growth rate matters enormously. 5% monthly growth still leaves long runway; 15%+ often reaches profitability. Most early-stage startups aim for 18-24 months runway when raising to buy time for traction.

Run it with sensible defaults

Using cash on hand of 500,000, monthly burn of 40,000, current monthly revenue of 10,000, monthly revenue growth of 15%, the calculation works out to 10 months to profit. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Cash on Hand, Monthly Burn, Current Monthly Revenue, and Monthly Revenue Growth — do not pull with equal force. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

How the math works

Simulate month by month: balance -= (burn - revenue). Revenue grows at monthly growth rate. Stop when balance ≤ 0 or revenue ≥ burn.

What the score tells you

Headline financial numbers — income, savings, debt — each tell part of the story. This calculation stitches several together into a single read you can track over time. The value is in the direction, not the absolute number.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.

Worked example

Imagine a B2B software startup with the following profile:

• Cash on hand: 300,000
• Monthly burn (operating costs): 50,000
• Current monthly revenue: 5,000
• Monthly revenue growth rate: 10%

The calculator models month-by-month progression. At month 1, net burn is 45,000 (50,000 cost minus 5,000 revenue). Cash falls to 255,000. At month 2, revenue grows to 5,500; net burn becomes 44,500. The balance shrinks each month, but more slowly as revenue rises. By month 13, revenue has grown to 13,000 per month, nearly meeting the 50,000 burn. By month 15, revenue exceeds burn, and the company reaches cash-flow break-even. The calculator returns 15 months.

When this metric matters

Runway appears most frequently in fundraising conversations. Founders use it to set targets for capital raises. Investors use it to assess how much time a startup has to demonstrate traction before the next funding event. Internally, teams track runway changes quarterly as revenue and burn evolve, spotting trends early.

The metric also surfaces during cost-cutting discussions. If runway drops below desired levels, leadership can model scenarios: cutting burn by 20%, accelerating revenue by specific amounts, or raising capital sooner. Each adjustment shows its effect on months remaining.

What the result captures and what it misses

The calculator captures the interplay between cash reserves, monthly expenses net of revenue, and revenue growth rate. It models a linear growth pattern and assumes burn and revenue continue as stated.

The result does not account for seasonal revenue swings, irregular large expenses, changes in burn rate, fundraising timelines, customer concentration risk, or timing mismatches between cash outflow and collection. It treats growth as constant month-to-month, which rarely holds in practice. A startup may see lumpy revenue, one-time costs, or sudden shifts in hiring plans. The output is a snapshot under stated assumptions, not a forecast.

Educational purpose

This calculator illustrates how cash, burn, and revenue interact over time. The result is for educational modeling only and does not predict actual business outcomes.