Startup Runway & Burn Rate Simulator

Team & Spend

Headcount 5

Marketing spend / mo $8,000

Price per customer / mo $120

Monthly churn rate 4.0%

Company Status

Seed round closed. $500,000 in the bank, 20 early customers. Adjust the dials to plan your growth.

Cash on hand

$500,000

Runway

∞

MRR

$2,400

Burn multiple

—

How it works

Each simulated month, the model advances the company's cash and customer base with real SaaS-startup mechanics:

effCAC = 300 · (1 + 0.6 · max(0, spend − 3000h) / (3000h + 1))
newCust = spend / effCAC
churned = customers · churnRate
customers += newCust − churned
MRR = customers · price
payroll = 7500 · h   (h = headcount)
expenses = payroll + spend + 2000 (overhead)
netCashFlow = MRR − expenses
cash += netCashFlow

Marketing has diminishing returns once spend outpaces the team's capacity to onboard and support customers (roughly $3,000/month of spend per employee) — pouring money into ads without hiring sales/support raises effective customer-acquisition cost (CAC). Runway is cash ÷ current monthly net burn. Burn multiple — a real metric VCs use — is net burn ÷ net-new MRR this month; below 1 is excellent capital efficiency, above 3 is a red flag. Bars turn red once cash reaches zero: that's the month the company runs out of money without new financing.

Headcount — more people raise fixed payroll burn but also raise the spend threshold before marketing gets inefficient.
Marketing spend — drives new-customer acquisition, subject to diminishing returns above.
Price per customer — monthly subscription price; higher price raises MRR per customer but every SaaS product has a real-world ceiling before churn rises (not modeled here — you set it directly).
Churn rate — the fraction of the customer base that cancels each month; the single biggest lever on long-run growth.
Raise Series A — injects $1,000,000 of fresh cash, resetting the runway clock without changing unit economics.

Month 0 / 36

Cash on hand Cash depleted Monthly recurring revenue

⚠ Couldn't load the 3D engineThree.js failed to load from the CDN. Check your connection and reload.