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CAC payback checker
Give it CAC, margins and cohort profit. Get profit to CAC ratios, a scale-or-fix call, scored out of 100.
CAC payback checker is a free AI skill for the job "Track your numbers". Give the instructions to an AI assistant that supports the required files and tools, then review its output.
Free · No account · Made by AI Blocks · Thinking: high
What it does
CAC is what you pay to win a customer: total ad spend divided by new customers. Payback asks whether the profit from that customer covers the cost, and how fast. Two checks answer different questions. The first order check asks if each new customer is paid back at once. The window ratio (lifetime gross profit divided by CAC over 30, 90 or 180 days) asks how quickly. This skill runs both. It uses gross profit, not revenue, over a fixed window, never "lifetime" without an end. It rates the ratio in bands, and it keeps the bands for different windows apart because two sources use different ones. It sets a target CAC, a ceiling and a bad-month ceiling, a floor from your CPC and conversion rate, and says if each new customer is more or less profitable than the last. It links to the lifetime gross profit to CAC checker…
You give it
- CAC, average order value after refunds, product cost and fulfilment per order
- Gross profit per customer at 30, 90 and 180 days
- Lifetime orders from your oldest cohort
- Product type (one-off, consumable or subscription)
- Cash you can use to fund payback, and CPC and conversion rate (both optional)
- Spreadsheet (optional)
- Your question (optional)
You get
- Contribution per order and the first order ratio
- The profit to CAC ratio on each window, with its band
- A target, ceiling and floor CAC, and payback in days or months
- Whether each new customer is more or less profitable than the last
- A scale, hold or fix call and a score out of 100 for payback safety
Use it when
- Ad spend is rising and you do not know if you can keep scaling.
- You want a CAC number to give your media buyer.
- You lose money on the first order on purpose and need to know how long payback takes.
How to use it
- Start a chat with the skill. Open it if you added it to your AI, or copy it and paste it in.
- Paste your monthly ad spend and new customers, your order margins and your cohort gross profit.
- Say what type of store you run, how much cash you have to wait for payback, and your stage.
- Read the first order check first, then the ratio on your chosen window.
- Act on the CAC figure it says to hit, and run it again next month.