B2B SaaS Metrics Calculator
CAC, LTV, payback and the logos behind your ARR target, from numbers you already know.
Four numbers decide whether a B2B SaaS business compounds or just spins: what a customer costs to win, what they pay a year, what share of that survives the cost of serving them, and how many of them stay. This B2B SaaS calculator turns those into the metrics operators and investors actually argue about: lifetime value, the LTV to CAC ratio, CAC payback in months, and how many new logos your ARR target needs. Gross margin sits inside the math deliberately, because lifetime revenue is a vanity number and lifetime gross profit is the one that pays for the next hire. It runs in your browser and nothing you enter is stored.
Reading SaaS unit economics without fooling yourself
- Build lifetime value on gross profit, not revenue. Support, hosting and onboarding are real costs, and an LTV that ignores them flatters every decision downstream of it.
- Fully load CAC: paid spend, sales and marketing salaries, commission, tooling and the agency invoice, divided by the customers those dollars actually produced.
- Payback is the cash question and LTV to CAC is the profit question. A healthy ratio with a twenty month payback still starves a company with no funding behind it.
- Segment before you act on any of it. Blended metrics hide the reality that self serve customers often pay back in weeks while enterprise deals take quarters and are worth the wait.
- Use logo churn here, not revenue churn. Revenue churn can look calm while the customer base quietly empties, and expansion revenue masks both if you net them together.
- Treat 3 to 1 as a rule of thumb rather than a target to engineer. Cutting acquisition spend always lifts the ratio, and frequently shrinks the company at the same time.
Example output
CAC / ACV / margin / churn / ARR target: $14,000 CAC, $18,000 ACV, 80% gross margin, 18% annual churn, $2,400,000 new ARR target
Annual gross profit per customer: $14,400 ($18,000 ACV at 80% gross margin) CAC payback: 11.7 months ($14,000 CAC divided by $1,200 of monthly gross profit) Under twelve months is the band most B2B SaaS operators aim for. Treat it as a rule of thumb, not a law. Lifetime value: $80,000 ($14,400 of yearly gross profit divided by 18% annual churn) LTV to CAC: 5.7 to 1 Average customer life: 5.6 years at that churn rate. 3 to 1 is the rule of thumb quoted across SaaS, not a promise. You are above it, which usually means you can afford to spend more to grow. To add $2,400,000 of new ARR: 134 new customers at $18,000 ACV, about 11.2 a month. Winning them costs roughly $1,876,000 at today's CAC.
Frequently asked questions
- What is B2B SaaS?
- B2B SaaS is software sold to businesses as a subscription rather than a one time license, delivered over the web and billed monthly or annually. The model trades a large upfront payment for recurring revenue, which is exactly why acquisition cost, retention and gross margin matter more than any single closed deal does.
- What is a good LTV to CAC ratio?
- 3 to 1 is the figure quoted across the industry as a rule of thumb, not a law of nature. Well below it usually means acquisition costs too much or customers leave too fast. Far above it often means you are underinvesting in growth and handing market share to a competitor who is not.
- What is CAC payback?
- CAC payback is how many months of gross profit from one customer it takes to repay what you spent winning them: CAC divided by monthly gross profit per customer. It is a cash flow measure, so it decides how fast you can grow without outside money, which is something the LTV to CAC ratio never tells you.
- Why is this free, and what's the catch?
- No catch and no signup. This tool is funded by EaseClaw, an AI agent that finds warm buyers on LinkedIn, reaches out for you and books the meetings. If the free tool is useful, some people try the free trial. That's the whole business model.