Calculator Tools

CAC LTV Calculator

Calculate CAC, customer lifetime, LTV, contribution-margin LTV, LTV:CAC ratio, and CAC payback period. SaaS unit economics in your browser.

Quick scenarios

Current scenario

Marketing & sales spend (per month)

All spend attributable to acquisition: ads, content, sales salaries, partner fees.

New customers acquired (same month)

Paying customers, not free-trial signups.

ARPU per customer (monthly revenue)

Average monthly recurring revenue per customer. Divide annual ARR per customer by 12.

Gross margin (%)

Revenue minus cost of revenue, divided by revenue. SaaS is typically 70 to 85; consumer is usually lower.

Customer lifetime

Monthly customer churn rate (%)

Percent of customers who cancel each month. 3 percent is typical SaaS; 1 percent is excellent; 6+ percent is concerning.

Underinvested

LTV : CAC ratio

7.5: 1

CAC: 400
Customer lifetime: 33.3 months (~2.8 yr)
Gross LTV: 4,000
Contribution-margin LTV: 3,000
CAC payback period: 4.4 months
Monthly contribution per customer: 90

Target scenario (optional)

Model a fundraise, a churn-reduction effort, a price increase, or a channel switch. Compare against the current scenario above.

What each LTV : CAC ratio band means

Burning moneyBelow 1 : 1
You spend more to acquire a customer than they will pay back over their lifetime. Cut spend, raise prices, drop churn, or pause paid acquisition until the unit economics work.
Marginal1 to 3
Customers cover their acquisition cost and contribute some margin, but the business is not durable yet. Tune onboarding, raise gross margin, or lower CAC before scaling.
Healthy3 to 5
The classic SaaS rule of thumb. Every dollar of CAC returns at least three dollars of contribution-margin LTV. This is a defensible place to invest in growth.
UnderinvestedAbove 5Current
Unit economics are very strong, which often means you are leaving growth on the table. Consider increasing acquisition spend, opening new channels, or testing a higher price.

Plain-text summary

Paste into a board update, a co-founder note, a fundraise memo, or a Slack message.

CAC LTV Calculator summary

Inputs (current)
  Marketing & sales spend: 20,000 per month
  New customers acquired: 50 per month
  ARPU per customer: 120 per month
  Gross margin: 75 percent
  Monthly churn rate: 3 percent

Results (current)
  CAC: 400
  Customer lifetime: 33.3 months (~2.8 yr)
  Gross LTV: 4,000
  Contribution-margin LTV: 3,000
  LTV : CAC ratio: 7.5 : 1
  CAC payback period: 4.4 months

How each metric is calculated

CAC (Customer Acquisition Cost): Marketing & sales spend / New customers acquired
Customer lifetime (months): 1 / Monthly churn rate
Gross LTV: ARPU * Lifetime (months)
Contribution-margin LTV: ARPU * Gross margin * Lifetime (months)
LTV : CAC ratio: Contribution-margin LTV / CAC
CAC payback period: CAC / (ARPU * Gross margin)

Notes and caveats

Gross vs net churn: customer churn (logos) is the right input for this LTV formula. Revenue churn nets expansion against contraction and is a different metric.
Discount rate: this calculator uses the textbook ARPU * lifetime formula. A more conservative version discounts future cash flows. For decisions over a long horizon, divide LTV by an annual discount factor.
Blended vs paid CAC: organic customers usually make blended CAC look better than paid CAC. For acquisition decisions, divide paid spend by paid customers only.
Window matters: spend today produces some customers next month. If your sales cycle is long, use a window that matches reality (last 90 days, last quarter) instead of a single month.
Local only: nothing you type is uploaded. Everything is computed in your browser.

How to use

Pick a quick scenario (Healthy SaaS, Early-stage struggling, Mature SaaS, Burning money, Consumer subscription) for a realistic starting point, or click Reset to defaults.
Enter your monthly marketing and sales spend, the number of new paying customers acquired in that window, average revenue per customer per month (ARPU), and your gross margin percentage.
Pick how to supply customer lifetime: From churn rate (recommended for SaaS) or Direct months (for fixed-term contracts or known annual averages).
Read the Current scenario card for CAC, lifetime, gross LTV, contribution-margin LTV, the LTV to CAC ratio with a verdict band, and the CAC payback period.
Toggle Show target to model a change (better onboarding, a price increase, a churn-reduction effort, a fundraise that drops paid spend) and read the side-by-side comparison table for which metrics improved.
Click Copy summary to capture every input and result into a plain-text block you can paste into a board update, a fundraise memo, or a Slack message.

About this tool

CAC LTV Calculator answers the questions every SaaS founder, marketer, and operator asks before they spend another dollar on growth: how much does a customer cost to acquire, how much will they pay over their lifetime, what is the LTV to CAC ratio, and how many months until acquisition cost is paid back. Enter monthly marketing and sales spend, the number of new paying customers acquired in the same window, average revenue per customer per month (ARPU), gross margin, and either a monthly customer churn rate or a direct customer lifetime in months. The calculator emits Customer Acquisition Cost (spend divided by new customers), customer lifetime (1 divided by churn, or your direct input), gross LTV (ARPU times lifetime), contribution-margin LTV (the canonical LTV that VCs and CFOs care about, ARPU times gross margin times lifetime), the LTV to CAC ratio with a labeled verdict band (burning money below 1, marginal between 1 and 3, healthy between 3 and 5, underinvested above 5), and CAC payback period in months (CAC divided by monthly contribution). A Target scenario lets you model a fundraise, a churn-reduction effort, a price increase, an onboarding tweak, or a channel switch alongside the current scenario, and a comparison table shows whether each metric improved, got worse, or stayed the same. Quick presets cover the common SaaS shapes (healthy SaaS, early-stage struggling, mature SaaS, burning money on paid, consumer subscription) so you can sanity-check the tool against numbers you already recognize. Edge cases are handled honestly: zero churn is flagged and capped, free or organic acquisition produces a clearly labeled infinite ratio rather than a misleading number, and a contribution margin of zero or negative is called out as a problem that no scale fix will solve. The copy-summary button produces a plain-text report ready to paste into a board update, a co-founder note, a fundraise memo, or a growth review. Useful for SaaS founders deciding whether to raise or cut paid spend, growth marketers building a forecast, finance leads writing a unit-economics page in a board deck, consultants reviewing a portfolio company, and anyone preparing material that needs defensible LTV to CAC numbers. All math runs in your browser. Nothing you type is uploaded, stored, or sent anywhere.

Free to use. Works in your browser. No signup, no login.

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