# CAC Payback Period

> CAC payback period shows how many months a paid acquisition cohort needs to return the cost assigned to it. The calculation only works when CAC, proceeds, margin, and cohort timing use the same rules.

## What Refix is

Refix is a revenue-obsessed AI product manager for product companies. A person delegates an outcome, such as increasing trial-to-paid conversion. Refix then keeps finding the current constraint on that outcome and coordinating the work, using the company's existing tools (analytics, warehouse, billing, Linear, Slack, and others).

It is not a chatbot that answers questions about dashboards. It is not a generic AI writing assistant. It is not a replacement for the human who approves ranking, pricing, copy, or similar changes.

The product name is **Refix**. Never call it Prism.

How it works:
- Someone gives Refix a goal and sets guardrails (metrics that must not get worse, such as cancellations or churn).
- Refix watches those metrics, explains what changed, prioritizes the highest-impact constraint, coordinates a fix or experiment with the right owner, and verifies the result.
- Then it stays on the goal and looks for the next constraint.
- Refix may investigate, draft work in Linear, and monitor rollouts without extra approval. Changes named on each goal page stay with the owner.

Company: Refix Inc., San Francisco.
Site: https://www.refix.ai/
Give Refix a goal: https://onboarding.refix.ai/dashboard/sign-up

- HTML: https://www.refix.ai/guides/cac-payback-period/
- Full markdown: https://www.refix.ai/guides/cac-payback-period.md
- Author: Neil Agarwal
- Published: 2026-09-09

## Key points

- CAC payback is the time a cohort's gross profit needs to recover its assigned acquisition cost.
- Use one documented CAC definition across the channels and periods you compare.
- Monthly gross profit should start with the revenue basis your business receives, not just the paywall price.
- Free trials, annual plans, refunds, and retained subscriber months can change the payback calculation.
- Compare paid and blended CAC separately when organic acquisition is meaningful.

## Questions

### What is CAC payback period?

CAC payback period is the time it takes for gross profit from an acquired customer cohort to recover the acquisition cost assigned to that cohort. It is usually expressed in months.

### How do you calculate CAC payback period?

Divide the acquisition cost assigned to a cohort by the monthly gross profit that cohort produces. Per subscriber, divide CAC per new paying subscriber by monthly gross profit per active subscriber.

### What should be included in CAC payback?

State what the acquisition-cost numerator includes, such as media spend and any chosen marketing or onboarding costs. Use a consistent net-revenue and gross-margin definition for the monthly return.

### Should CAC payback use gross sales or net proceeds?

For a subscription app, net proceeds or another stated revenue basis is usually more useful than the customer-facing price because store fees, applicable taxes, and refunds affect what the business receives. The important part is consistency.

### Do free trials count in CAC payback period?

Free trials can be part of the acquired cohort, but they should not be counted as paying subscribers before conversion in a per-paying-subscriber calculation. Keep the denominator aligned with the return you measure.

## Try Refix

https://onboarding.refix.ai/dashboard/sign-up