Gross Margin to Fund Growth Calculator
See how much growth your gross margin can self-fund — the new customers and MRR you can buy from cash left after operating costs.
How it works
Gross profit = revenue × margin · Growth cash = gross profit − opex · New customers = growth cash ÷ CAC · New MRR = customers × ARPA
Every dollar of gross margin left after operating costs is capital you can plow back into acquisition without raising money. Dividing that free cash by your cost to acquire a customer gives the customers you can buy each month, and multiplying by their monthly revenue shows the MRR — and growth rate — you can sustain on your own margin. Higher margin or lower fixed costs directly widen the self-funded growth you can afford.
Worked example
On $100,000 of revenue at a 70% gross margin, gross profit is $70,000. After $45,000 of operating costs, $25,000 is free for growth. At a $1,200 CAC that funds about 20 new customers a month; at $200 of monthly revenue each, that adds $4,166 of MRR — roughly 4.2% self-funded monthly growth.
Frequently asked questions
What is "cash available for growth"?
It is gross profit minus operating costs that are not acquisition spend — the money left over that you could redirect into marketing and sales. If that figure is negative, you cannot self-fund growth until margin rises or costs fall.
Why does gross margin matter so much for growth?
Growth is bought with the cash margin throws off. A business at an 80% margin frees far more per revenue dollar to reinvest than one at 40%, which is why high-margin models can compound growth without constant fundraising.
Does this account for churn?
No — it estimates the new MRR you can add each month, not net growth after losses. Pair it with a churn or LTV:CAC view to see whether the customers you acquire stay long enough to pay back their acquisition cost.
Related calculators
Educational estimate, not financial advice.