What inputs does the CAC Calculator need?

It takes 5 inputs: salesAndMarketingSpend, customersAcquired, arpu, grossMargin (default 80), monthlyChurn (default 5). Outputs returned: cac, paybackMonths, ltv, ltvCacRatio.

Can I verify the CAC Calculator with a worked example?

Yes. With spend = $20,000, customers = 100, arpu = $50, grossMargin = 80%, monthlyChurn = 3%. the tool returns cac = $200, payback = 5 months, ltv ≈ $1,333, ltv:cac ≈ 6.7×.

Where does the CAC Calculator get its benchmark data?

Reference data is sourced from: OpenView SaaS Benchmarks 2024 (CAC payback percentiles) (as of 2024); SaaS Capital Annual Survey (as of 2024).

What can the CAC Calculator not tell me?

Known limitations: Blended CAC hides channel-level economics. Organic-heavy businesses with a small paid budget will look stronger than they are. LTV:CAC guidance (often quoted as 3:1) is industry lore; benchmarks from OpenView and SaaS Capital vary by stage and vertical.

Methodology: CAC Calculator

1. Scope

Computes customer acquisition cost from total acquisition spend divided by customers acquired, plus payback-month and LTV:CAC ratio. It does not attribute spend across channels or model marketing-mix effects.

2. Inputs and outputs

Inputs

salesAndMarketingSpend number (currency)
customersAcquired number
arpu number (currency/mo)
grossMargin percent default: 80
monthlyChurn percent default: 5

Outputs

cac

spend / customers.
paybackMonths

cac / (arpu × grossMargin).
ltv

arpu × grossMargin / monthlyChurn.
ltvCacRatio

ltv / cac.

Engine source: src/lib/cac-calculator/engine.ts

3. Formula / scoring logic

cac            = sales_marketing_spend / customers_acquired
payback_months = cac / (arpu * gross_margin)
ltv            = (arpu * gross_margin) / monthly_churn
ltv_cac_ratio  = ltv / cac

4. Assumptions

Spend is fully-loaded: paid ads, sales salaries, tooling, and attributed content cost.
Customers-acquired is net-new, not re-activated.
ARPU and margin are steady-state.

5. Data sources

OpenView SaaS Benchmarks 2024 (CAC payback percentiles) as of 2024
SaaS Capital Annual Survey as of 2024

6. Known limitations

Blended CAC hides channel-level economics. Organic-heavy businesses with a small paid budget will look stronger than they are.
LTV:CAC guidance (often quoted as 3:1) is industry lore; benchmarks from OpenView and SaaS Capital vary by stage and vertical.

7. Reproducibility

Input
spend = $20,000, customers = 100, arpu = $50, grossMargin = 80%, monthlyChurn = 3%.

Expected output
cac = $200, payback = 5 months, ltv ≈ $1,333, ltv:cac ≈ 6.7×.

8. Change log

2026-04-24 methodology page first published.

Worked example

Run live against the same engine this site ships (/engines/cac-calculator.js). The inputs and outputs below are recomputed on every build and independently re-verified in CI — they are never hand-authored.

Input

tool: cac_calculator
sales_marketing_spend: 32000
new_customers: 40
arpu_monthly: 129
gross_margin_percent: 78
monthly_churn_percent: 4

Output

primaryLabel: Customer acquisition cost
primaryValue: 800
primaryFormat: currency
summary: CAC is spend divided by acquired customers in the same period.
metrics[0].label: Payback period
metrics[0].value: 7.95
metrics[0].format: months
metrics[1].label: Gross profit / user / mo
metrics[1].value: 100.62
metrics[1].format: currency
metrics[2].label: LTV
metrics[2].value: 2515.5
metrics[2].format: currency
metrics[3].label: LTV:CAC
metrics[3].value: 3.14
metrics[3].format: number
assumptionsEcho.sales_marketing_spend: 32000
assumptionsEcho.new_customers: 40
assumptionsEcho.arpu_monthly: 129
assumptionsEcho.gross_margin_percent: 78
assumptionsEcho.monthly_churn_percent: 4

Frequently asked questions

What does the CAC Calculator calculate?: Computes customer acquisition cost from total acquisition spend divided by customers acquired, plus payback-month and LTV:CAC ratio. It does not attribute spend across channels or model marketing-mix effects.
What inputs does the CAC Calculator need?: It takes 5 inputs: salesAndMarketingSpend, customersAcquired, arpu, grossMargin (default 80), monthlyChurn (default 5). Outputs returned: cac, paybackMonths, ltv, ltvCacRatio.
What formula does the CAC Calculator use?: The exact computation is: cac = sales_marketing_spend / customers_acquired; payback_months = cac / (arpu * gross_margin); ltv = (arpu * gross_margin) / monthly_churn; ltv_cac_ratio = ltv / cac
Can I verify the CAC Calculator with a worked example?: Yes. With spend = $20,000, customers = 100, arpu = $50, grossMargin = 80%, monthlyChurn = 3%. the tool returns cac = $200, payback = 5 months, ltv ≈ $1,333, ltv:cac ≈ 6.7×.
Where does the CAC Calculator get its benchmark data?: Reference data is sourced from: OpenView SaaS Benchmarks 2024 (CAC payback percentiles) (as of 2024); SaaS Capital Annual Survey (as of 2024).
What can the CAC Calculator not tell me?: Known limitations: Blended CAC hides channel-level economics. Organic-heavy businesses with a small paid budget will look stronger than they are. LTV:CAC guidance (often quoted as 3:1) is industry lore; benchmarks from OpenView and SaaS Capital vary by stage and vertical.