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Free tool · for founders

Is your growth actually working?

Five numbers in, and you get your CAC, your LTV, the ratio between them, and how long it takes to earn a customer back. The numbers investors ask for, and most founders can't answer.

£
£
%
The share of revenue left after the cost of delivering it. SaaS is often 70 to 90%.
%
The share of customers you lose each month. 4% a month is roughly a two-year average life.
LTV to CAC ratio
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CAC (cost to acquire)
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LTV (lifetime value)
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CAC payback
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Avg customer life
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Enter your numbers
Rules of thumb: an LTV to CAC ratio of 3 or higher is healthy, and below 1 means you lose money on every customer you acquire. You want to earn your CAC back in under a year for most software. And retention is the biggest lever on all three, because lowering churn lengthens the life, lifts the LTV and shortens the payback at once.

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About this tool

What the Unit Economics Calculator does.

Enter what it costs to win a customer, what one is worth over their life and how long they stay, and it returns CAC, LTV, the ratio between them, the payback period, and a verdict on whether the growth in front of you is healthy or expensive. Growth feels like proof. These are the numbers that say whether it is.

Who it is for. Founders with revenue moving and a nagging sense the maths might not work, and anyone about to spend on acquisition at scale.

What it will not do. It does not import your data or fix a broken model. If the ratio is poor, the answer is usually in the price or in who you are selling to, and no calculator settles that for you.

What is a good LTV to CAC ratio?
Three to one is the number everybody quotes, and it is a reasonable place to start. Payback matters at least as much at early stage: money spent today that comes back in four months is a different business to money that comes back in eighteen.
How do I work out LTV before I have churn data?
Use the contract length you actually sell and be honest about it. Assuming lifetimes you have not observed is the most common way this calculation flatters a business that is not working yet.
My economics look bad. What moves them fastest?
Price, almost always. It is the cheapest experiment available and it lands straight on gross profit and payback, where a twenty per cent rise can do more than a quarter of acquisition work.
Product Pieces · Senior product, by the piece. productpieces.io