What LTV:CAC ratio should I aim for with this calculator?

As a rule of thumb, a ratio around 3:1–4:1 is considered healthy: you generate $3–$4 in lifetime value for every $1 spent on CAC. Ratios below 1:1 mean you’re losing money on each customer, while numbers above ~5:1 often signal that you’re under-investing in growth rather than being “super efficient.”

When should I use the SaaS (Churn-based) vs SaaS (Lifespan) vs Direct Inputs models?

Use SaaS (Churn-based) if you track monthly churn and margin; this follows the common formula LTV = ARPU × Gross Margin ÷ Churn Rate, optionally adjusted by a discount rate. Use SaaS (Lifespan) if you have a solid estimate of average customer lifespan in months (LTV ≈ ARPU × Gross Margin × Lifespan). Use Direct Inputs when you already know LTV and CAC from your own modeling and just want the ratio and surplus.

Why does the calculator also show CAC payback in months alongside the LTV:CAC ratio?

LTV:CAC tells you how profitable each acquired customer is over their lifetime, but CAC payback shows how fast you recover your acquisition spend. Investors and operators look at both: a strong ratio with a very long payback can still strain cash, while a quick payback with a weak ratio can cap long-term profitability.

What does the “Apply Discount Rate (NPV)” toggle actually change in my LTV:CAC results?

Turning this on discounts future monthly cash flows back to today using your annual discount rate, so LTV is lower but more realistic for long lifetimes or higher risk. It’s useful for later-stage SaaS or when capital has a real cost; early-stage teams often look at the non-discounted version first, then sanity-check with NPV-adjusted LTV.

LTV:CAC Ratio Calculator – Understand SaaS Customer Profitability

LTV:CAC Ratio Calculator (SaaS)

Essential SaaS unit economics: compute LTV:CAC ratio and CAC payback using direct inputs or a churn-based best-practice model. Includes clean scenarios and guidance.

Model

LTV = Monthly ARPU × Gross Margin ÷ Monthly Churn. Optionally apply a discount rate (NPV).

Monthly ARPU

Gross Margin

Monthly Churn Rate

Apply Discount Rate (NPV)

Annual Discount Rate

Average Lifespan (months)

Lifetime Value (LTV)

CAC (Customer Acquisition Cost)

Results

LTV:CAC (x)
Category
CAC Payback (months)
Lifetime Value (LTV) $
Monthly Contribution $
Lifetime Revenue (pre‑margin) $
CAC $
Surplus over CAC $
Model Used

What is LTV:CAC Ratio?

The LTV:CAC ratio compares customer lifetime value (LTV) with customer acquisition cost (CAC) to show how efficiently a business converts acquisition spend into long-term gross profit.

In SaaS and subscription models, this ratio anchors unit economics: it links monetization, retention, churn, gross margin, and acquisition efficiency into a single signal of whether growth is value-accretive or value-destructive.

Operators and investors generally consider 3:1 healthy; below 2:1 signals inefficient spend, while very high ratios can indicate under-investment in growth despite strong retention and monetization.

Formula

Example

A SaaS product has:

ARPU: $50/month
Gross margin: 75%
Monthly churn: 4%
CAC: $150

LTV = (50 × 0.75) / 0.04 = $937.50

LTV:CAC = 937.50 / 150 = 6.25:1

This ratio reflects high-efficiency growth, strong retention economics, and headroom to scale acquisition while staying comfortably above the 3:1 benchmark.

How to Use the LTV:CAC Ratio Calculator

Use this calculator to estimate customer lifetime value (LTV), compare it to your customer acquisition cost (CAC), and see whether your SaaS unit economics are strong enough to scale.

Select the calculation model
- At the top, pick SaaS (Churn-based), SaaS (Lifespan), or Direct Inputs depending on whether you want LTV derived from churn, from average lifespan, or entered directly.
Enter your revenue and retention inputs
- - For Churn-based, type your Monthly ARPU, Gross Margin %, and Monthly Churn Rate %.
- For Lifespan, enter Monthly ARPU, Gross Margin %, and Average Lifespan (months).
- For Direct Inputs, just enter your Lifetime Value (LTV).
Add CAC and optional discount rate
- - Fill in CAC (Customer Acquisition Cost) for all models.
- In the churn-based model, use the Apply Discount Rate (NPV) toggle and Annual Discount Rate % if you want an NPV-adjusted LTV based on the formula:
Review the results panel
- Check the LTV:CAC (x) value and the Category label to see whether your ratio is weak, acceptable, or excellent, then look at CAC Payback (months), Lifetime Value (LTV), Monthly Contribution, Lifetime Revenue, and Surplus over CAC to understand profitability per customer.
Iterate scenarios and compare
- Use the “Try scenarios” presets (if available) or tweak ARPU, churn/lifespan, margin, CAC, and discount rate to see how changes in pricing, retention, or acquisition efficiency shift your LTV:CAC and payback before committing budget.

Frequently Asked Questions

As a rule of thumb, a ratio around 3:1–4:1 is considered healthy: you generate $3–$4 in lifetime value for every $1 spent on CAC. Ratios below 1:1 mean you’re losing money on each customer, while numbers above ~5:1 often signal that you’re under-investing in growth rather than being “super efficient.”
Use SaaS (Churn-based) if you track monthly churn and margin; this follows the common formula LTV = ARPU × Gross Margin ÷ Churn Rate, optionally adjusted by a discount rate. Use SaaS (Lifespan) if you have a solid estimate of average customer lifespan in months (LTV ≈ ARPU × Gross Margin × Lifespan). Use Direct Inputs when you already know LTV and CAC from your own modeling and just want the ratio and surplus.
LTV:CAC tells you how profitable each acquired customer is over their lifetime, but CAC payback shows how fast you recover your acquisition spend. Investors and operators look at both: a strong ratio with a very long payback can still strain cash, while a quick payback with a weak ratio can cap long-term profitability.
Turning this on discounts future monthly cash flows back to today using your annual discount rate, so LTV is lower but more realistic for long lifetimes or higher risk. It’s useful for later-stage SaaS or when capital has a real cost; early-stage teams often look at the non-discounted version first, then sanity-check with NPV-adjusted LTV.

Methodology & Sources

Bibliography

Harvard Business School Online (2025). LTV/CAC Ratio: What It Is & How to Calculate It — Harvard Business School Online https://online.hbs.edu/blog/post/ltv-cac
Accessed 2025-11-27
Capchase (2022). How to Calculate Customer Lifetime Value (LTV Formula) — Capchase https://www.capchase.com/blog/how-to-calculate-customer-lifetime-value-ltv-formula
Accessed 2025-11-27
Stripe (2025). CAC SaaS: A Guide for Businesses — Stripe https://stripe.com/resources/more/cac-in-saas
Accessed 2025-11-27

LTV:CAC Ratio Calculator (SaaS)

Results

What It Means

What is LTV:CAC Ratio?

Formula

Example

How to Use the LTV:CAC Ratio Calculator

Select the calculation model

Enter your revenue and retention inputs

Add CAC and optional discount rate

Review the results panel

Iterate scenarios and compare

Frequently Asked Questions

Methodology & Sources

Bibliography

Other Calculators in SaaS Metrics

LTV Calculator (Lifetime Value)

Customer Acquisition Cost (CAC) Calculator

Churn Rate Calculator

Monthly Recurring Revenue (MRR) Calculator

Annual Recurring Revenue (ARR) Calculator

Payback Period Calculator