What is Startup Runway & Burn Rate Calculator?

Free startup runway calculator with month-by-month cash projection, revenue growth modeling, and Paul Graham's default-alive check. Shows when you'll hit profitability vs run out of cash. No signup required.

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Free Startup Runway & Burn Rate Calculator

Project your startup's cash balance month-by-month with revenue growth and expense growth assumptions. Identifies whether you're "default alive" (reach profitability before running out of cash, per Paul Graham 2015) or default dead. Surfaces the specific months when cash runs out and when revenue overtakes expenses.

Today

$
$

Total monthly expenses: payroll, software, rent, etc. Pre-revenue offsets.

$

Growth

%

Honest seed-stage SaaS: 5-15%/mo. Series A: 8-12%/mo. Be brutally realistic — early growth from $0 is easier than later growth from $1M.

%

Often 0-3%/mo. Hiring adds steps, not curves.

Runway

14 months

Month-by-month projection

MonthRevenueExpensesNetCash
1$10,000$50,000-$40,000$460,000
2$11,000$51,000-$40,000$420,000
3$12,100$52,020-$39,920$380,080
4$13,310$53,060-$39,750$340,330
5$14,641$54,122-$39,481$300,849
6$16,105$55,204-$39,099$261,750
7$17,716$56,308-$38,593$223,158
8$19,487$57,434-$37,947$185,210
9$21,436$58,583-$37,147$148,063
10$23,579$59,755-$36,175$111,888
11$25,937$60,950-$35,012$76,876
12$28,531$62,169-$33,638$43,238
13$31,384$63,412-$32,028$11,211
14$34,523$64,680-$30,158-$18,947
15$37,975$65,974-$27,999-$46,946
16$41,772$67,293-$25,521-$72,467
17$45,950$68,639-$22,690-$95,157
18$50,545$70,012-$19,467-$114,624
19$55,599$71,412-$15,813-$130,437
20$61,159$72,841-$11,681-$142,119
21$67,275$74,297-$7,022-$149,141
22$74,003$75,783-$1,781-$150,922
23$81,403$77,299+$4,104-$146,818
24$89,543$78,845+$10,698-$136,120
25$98,497$80,422+$18,075-$118,044
26$108,347$82,030+$26,317-$91,728
27$119,182$83,671+$35,511-$56,217
28$131,100$85,344+$45,756-$10,461
29$144,210$87,051+$57,159$46,698
30$158,631$88,792+$69,839$116,536
31$174,494$90,568+$83,926$200,462
32$191,943$92,379+$99,564$300,026
33$211,138$94,227+$116,911$416,937
34$232,252$96,112+$136,140$553,077
35$255,477$98,034+$157,443$710,520
36$281,024$99,994+$181,030$891,550
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Status

14 months

Net burn

$40,000/mo

Default alive vs default dead

Paul Graham introduced the “default alive” concept in 2015: a startup is default alive if it reaches profitability before running out of cash, given current growth. Default dead means current growth is too slow to break even before the money runs out — which means you must either grow faster or raise more capital.

The framing matters because most founders think of runway as a single number (“we have 14 months”) but it's actually a function of two curves: cash declining over time and revenue growing over time. The interesting question isn't “how many months of cash” — it's “does revenue catch up to expenses before cash hits zero?” This calculator runs both curves month-by-month.

Reasonable growth assumptions

  • Seed-stage SaaS: 10-20%/month MRR growth is healthy. 5-10%/month is mediocre.
  • Series A SaaS: 8-12%/month is healthy. Below 5%/month suggests product-market fit issues.
  • Marketplace / consumer: Typically lumpier; trailing 3-month average smooths the chart.
  • Don't assume YC-style 15%/week. That's a small subset of fast-growing companies. Mortal startups grow 5-15% PER MONTH.

When to raise

The conventional rule: start fundraising when you have 9-12 months of runway left. Fundraising takes 3-6 months when it goes well. You'll want a buffer to walk away from bad terms. If you only have 4 months of runway and need to raise, your leverage is gone — investors know it and the term sheets show it.

When to cut burn

If the calculator shows you're not default alive and fundraising isn't imminent, you need to cut. The fastest levers: pause non-essential hiring, renegotiate large vendor contracts (especially infrastructure), cut paid acquisition until it pays back faster, freeze marketing. Layoffs are last because the morale and execution hit can be larger than the cash saved.

Frequently Asked Questions

What is "default alive"?+

A term coined by Paul Graham (2015) describing a startup that reaches profitability with current growth before its cash runs out. Default dead = current growth won't cover the burn before money runs out. The point of the framing: most founders frame runway as months-of-cash; the better question is whether revenue catches expenses first.

What's a healthy growth rate?+

Seed-stage SaaS: 10-20% MRR growth/month. Series A: 8-12%/month. Below 5%/month at any stage suggests product-market-fit gaps. Don't assume YC-style 15%/week — that's a tiny subset of fast-growing companies. Most successful startups grow 5-15% PER MONTH, not per week.

Gross burn vs net burn?+

Gross burn = total monthly expenses (payroll, software, rent). Net burn = gross burn − revenue. Runway is calculated against net burn. For pre-revenue startups, gross burn ≈ net burn. As revenue grows, net burn shrinks toward zero (then becomes profit).

When should I start fundraising?+

Industry consensus: when you have 9-12 months of runway left. Fundraising takes 3-6 months when it goes well. Starting with only 4-6 months left destroys your leverage — investors know you have to take whatever terms they offer.

How do I extend runway?+

Fastest levers: pause non-essential hiring; renegotiate vendor contracts (especially infrastructure costs); cut paid acquisition until it pays back faster; freeze new marketing initiatives. Layoffs are last because the team-morale and execution hit can be larger than the cash saved.

Should I count signed contracts as revenue?+

Account for cash, not contracts. A $120k annual contract signed today might pay $10k/month if billed monthly, or $120k upfront if paid annually. The accounting recognition is separate from cash flow. For runway purposes, model what actually hits your bank account when.

What about one-time costs?+

Legal, conferences, big enterprise sales travel, equipment purchases — add these in the months they hit. The calculator uses smooth monthly assumptions; real cash flows are lumpier. For investor pitches and board reviews, build a proper month-by-month financial model with specific line items.

Is my data stored?+

No. All projections run in your browser. Cash, burn, and revenue never leave your device.

Disclaimer. Projections only. Real startups have lumpy revenue (annual contracts, milestone payments), step-wise expenses (hiring batches), and one-time costs (legal, conferences). Use this as a sanity check; build a proper financial model for board reviews.