How much runway should a startup have?

Rule of thumb: always maintain 18–24 months of runway. 12 months is the danger zone — not enough time to fundraise if growth stalls. Start fundraising at 9–12 months of runway remaining, as a Series A can take 3–6 months to close.

Burn rate is the monthly net cash consumption. Gross burn = total monthly expenses. Net burn = gross burn − revenue. As MRR grows, net burn decreases until break-even where net burn = 0. Post break-even, the company is cash-flow positive.

What is default alive vs default dead?

A startup is "default alive" if, at current growth rates, it will become profitable before running out of money — without raising more funding. "Default dead" means it will run out of cash first. Paul Graham's framework for assessing startup survival.

How do I extend runway without raising?

Options: reduce burn (hiring freeze, renegotiate contracts), increase MRR growth (focus on retention and expansion), convert monthly customers to annual (improves cash position), or sell prepaid annual plans for immediate cash.

What is the difference between gross and net burn?

Gross burn is total monthly expenses — salaries, hosting, tools. Net burn is gross burn minus revenue. A company with $45K expenses and $18K MRR has $27K net burn. As MRR grows, net burn falls even with flat expenses, extending runway.

Is my data sent to a server?

No. The runway projection runs entirely in your browser with JavaScript. No financial figures — cash balance, burn rate, or MRR — are uploaded, logged, or stored anywhere.

saas

Free SaaS Runway Calculator — Cash Runway & Break-Even Projection

Runway is the number of months a startup can operate before running out of cash, given the current burn rate and cash on hand. Break-even is the point where MRR equals monthly expenses. This calculator projects both, accounting for MRR growth reducing burn over time.

Free — No SignupRuns in BrowserData Never Uploaded

saas

Calculate how many months until you run out of cash, and your break-even point.

Months of cash runway accounting for MRR growth reducing net burn
Break-even month detection — when MRR first exceeds monthly expenses
Net and gross burn rate at current MRR
Default alive vs default dead verdict from Paul Graham's framework
24-month month-by-month projection table and cash balance chart
Client-side only — no financial figures are uploaded or stored

Features

Everything you need in one SaaS Runway Calculator

Growth-aware runway

Unlike a simple cash-over-burn estimate, this projects MRR growth shrinking net burn each month — so runway reflects reality rather than today's static burn rate.

Break-even detection

Pinpoints the exact month MRR overtakes expenses — the moment the business stops consuming cash and becomes self-sustaining.

Default alive verdict

Tells you whether you reach profitability before cash runs out — Paul Graham's single most important question for an early-stage company.

24-month projection

A month-by-month table and chart show cash balance, MRR, and net burn so the trajectory is concrete and actionable, not just a single number.

How It Works

How to use SaaS Runway Calculator

Enter cash balance and monthly burn

Input current cash on hand and total monthly expenses (salaries, tools, hosting, etc.).

Enter MRR and growth rate

Add current MRR and expected monthly MRR growth rate percentage.

See runway and break-even

The calculator shows months of runway, break-even month, and a 24-month burn/revenue projection.

Format Comparison

Runway benchmarks — how much is enough?

Runway remaining	Situation
Under 6 months	Danger zone — raise or cut burn immediately
6–12 months	Start fundraising or push hard toward break-even
12–18 months	Workable — focus on milestones for next raise
18–24 months	Healthy — common target right after a funding round
Default alive	Strongest position — reaches profitability before cash runs out

Troubleshooting

How to fix common syntax errors

Most “invalid JSON” failures come from a small set of mistakes. Paste the failing JSON above, click Validate, and the tool points you at the exact line and column.

Using gross burn instead of net burnrunway = $300K / $45K expenses = 6.7 months

Use net burn (expenses − MRR). With $18K MRR, net burn is $27K and real runway is 11 months — 40% longer. Gross-burn runway is only useful if you have zero revenue.

Assuming flat MRR with no growthgrowth = 0%

Even modest MRR growth extends runway significantly. At 8% monthly growth, net burn halves in ~9 months. Always model your realistic growth rate or you'll systematically underestimate runway.

Forgetting non-recurring annual expensesexpenses = monthly salaries only

Include annual costs (audit, D&O insurance, domain renewals, annual SaaS licenses) amortized monthly. A $12K/year audit adds $1K/month to burn.

Starting fundraising with under 6 months runwaycash = 4 months remaining, then start raise

A Series A takes 3–6 months to close. Start raising at 9–12 months of runway. Below 6 months you have almost no negotiating leverage and risk running out mid-process.

Treating "default alive" as safe without monitoringverdict = default alive, no monthly review

Default alive assumes projected growth holds. If growth slows, runway shrinks. Recalculate monthly with actual MRR figures and cut burn if growth underperforms by more than 20%.

Including undrawn credit lines in cash balancecash = $200K + $150K revolving credit = $350K

Only liquid cash counts for runway. Credit facilities can be withdrawn or frozen. Model cash-only runway and treat credit as a contingency buffer, not a primary resource.

FAQ

Frequently asked questions

Runway = Cash balance / Net monthly burn. Net burn = monthly expenses − MRR. If you have $300K cash and burn $30K/month net, you have 10 months of runway. Gross burn (before revenue) is different from net burn.

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References

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