B2B SaaS Unit Economics
Unit Economics
Calculator
Enter your numbers below to instantly calculate CAC, LTV, payback period, and how your unit economics compare to B2B SaaS benchmarks.
Your Inputs
Revenue
$
%
Sales & Marketing Spend
$
$
Pipeline
Derived Outputs
ACV
—
ARPA × 12
Customer Lifespan
—
1 ÷ Monthly Churn
LTV
—
Lifespan × ARPA
Actual CPL
—
Ad Spend ÷ Leads
Formula & Metric Reference — All 15 Metrics
Inputs
You enter this
Total MRR ÷ total active accounts. Use monthly, not annual.
You enter this
Customers lost this month ÷ customers at start of month × 100. Annual churn ÷ 12 for an estimate.
You enter this
Include: ad spend, sales salaries + commissions, marketing salaries, agency fees, tools (CRM, enrichment), content costs.
You enter this
Subset of S&M expenses. Used to calculate Actual CPL. Should be ≤ total S&M expenses.
You enter this
Define "lead" consistently — MQL, demo request, or trial signup. Used to calculate CPL and lead-to-customer conversion rate.
You enter this
Accounts that converted to paying this month. Used to calculate Actual CAC and lead-to-customer conversion rate.
Derived Outputs
ARPA × 12
Annualised revenue per account. Used as the basis for Target CAC Method 1. Higher ACV = higher allowable CAC.
1 ÷ Monthly Churn %
At 3.3% monthly churn: 1 ÷ 0.033 = ~30 months. Reducing churn from 3% to 2% extends lifespan from 33 to 50 months — a 52% LTV increase.
Lifespan × ARPA
Total revenue expected from one customer before they churn. The ceiling on how much you can rationally spend to acquire them.
Ad Spend ÷ New Leads
What you're currently paying per lead from paid channels. Compare against Target CPL to know if your bids are set correctly.
Key Outputs
ACV × 0.5
Rule of thumb: don't spend more than half your first-year contract value acquiring a customer. Conservative, contract-value-anchored ceiling.
LTV ÷ 6
Targets a minimum 6:1 LTV:CAC ratio. Retention-anchored — accounts for full customer value over their lifetime, not just year one.
(Method 1 + Method 2) ÷ 2
Balanced ceiling. Used as the primary CAC benchmark. If Actual CAC exceeds this, your S&M spend per customer is too high.
S&M Spend ÷ New Customers
Blended CAC across all channels. Include all S&M costs — not just ad spend. This is the number to benchmark against your Target CAC.
Actual CAC ÷ ARPA
How long before a customer generates enough revenue to cover their acquisition cost. Under 12 months = healthy. Over 18 months = capital intensive. Fix before scaling.
LTV ÷ Actual CAC
The core unit economics health metric. Below 3:1 = losing money on growth. 3–6:1 = acceptable. 6–8:1 = ideal. Above 8:1 = under-investing in growth.
Target CAC × (Customers ÷ Leads)
The maximum you should bid or pay per lead given your current lead-to-customer conversion rate. Use to set bid caps in Google Ads, Meta, and LinkedIn.
New Customers ÷ New Leads
The multiplier that connects CPL to CAC. A 10% improvement here drops your effective CAC by 10% with zero change to ad spend. Highest-leverage lever in most B2B SaaS funnels.
LTV : CAC Ratio
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Your return on every dollar spent acquiring a customer
036810+
S&M Payback Period
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Months to recover what you spent acquiring each customer
Actual CAC
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Total S&M spend ÷ new customers this month
Target CAC (Midpoint)
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Average of 50% ACV and 1/6th LTV methods
Target CPL
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Max you should pay per lead at your current lead-to-customer conversion rate
vs B2B SaaS Benchmarks
LTV:CAC Ratio
6:1 – 8:1 ideal
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Payback Period
<18 months
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Actual CAC vs Target
CAC ≤ Target CAC
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Is your CAC
engineerable?
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LTV:CAC below 3:1 = you're overpaying to acquire customers relative to what they're worth.
LTV:CAC 6:1–8:1 = ideal range. Below 6 = not enough return. Above 8 = you're under-investing in growth.
Target CPL helps you set bid caps in Google Ads, Meta, and LinkedIn so your paid channels stay within unit economics.
Payback under 12 months = healthy. 12–18 months = acceptable. Over 18 months = capital-intensive, fix before scaling.
