Unit Economics For Fitness: LTV, CAC Ceiling, and “Growth That Pays” (Simple Model)

Why CPL is not a decision metric

Cost per lead (CPL) is useful - but it’s not the truth.

The truth is: what does a member *return* over time, and what can you afford to spend to acquire them?

That’s unit economics: LTV, contribution margin, CAC, and payback.

Step 1: Calculate LTV (simple, practical version)

Use a straightforward model:

LTV = weekly price × average membership months × gross margin

Gross margin is your revenue after direct delivery costs (typically coaching/wages and any direct service costs) - use a reasonable estimate if you don’t know it precisely.

Example:

• weekly price AU$25

• average months 6

• gross margin 70%

LTV ≈ 25 × 26 × 0.70 ≈ AU$455

It doesn’t need to be perfect; it needs to be consistent.

Step 2: Define your CAC ceiling

Your CAC ceiling is the maximum you can spend per join and still be profitable.

A practical method:

• decide a payback window (e.g., 8–12 weeks)

• ensure you recover CAC inside that window

If your LTV is AU$900, you might set CAC ceiling at AU$250–$350 depending on margin and cashflow.

Step 3: Use decision rules (the part most gyms miss)

If CAC is above ceiling, you have three choices:

1) improve conversion (trial bookings, show rate, join rate)

2) improve LTV (price, retention, add-ons)

3) reduce cost (better targeting, better creative)

Most gyms only do #3.

But often the highest ROI fix is conversion or retention.

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Worked example: where to fix first

If you spend AU$4,000/month, generate 60 leads, and get 15 joins:

• CAC = AU$4,000 ÷ 15 = AU$267

If your CAC ceiling is AU$300, you’re fine.

If your CAC ceiling is AU$200, you need to fix a lever.

Before you cut ads, check:

1. Speed-to-lead

2. Show rate

3. Trial-to-join

A small conversion lift can move CAC dramatically.

Common mistakes

• Overestimating LTV

• Ignoring gross margin

• Not separating acquisition and retention levers

• Scaling spend without a CAC ceiling

• Making decisions from emotion

Implement this week

1) Calculate LTV (rough)

2) Set a CAC ceiling

3) Add CAC and LTV to your KPI set

4) Agree decision rules with your team

Growth should pay—not just look busy.