A fitness studio's membership count is the number everyone watches and the one that explains the least. A studio holding steady at 1,200 members while adding and losing 70 a month is spending its entire marketing budget on replacement, and its income statement will show flat revenue and rising acquisition cost without saying why. The economics live in cohorts — the members who joined in a given month, tracked for how long they stay and what they are worth — and in the arithmetic that connects acquisition spend to the contribution those cohorts produce.
Why does net member change mislead?
Net change nets two numbers that should be read separately. Joins and cancellations in a month; a studio with 42 joins and 38 cancellations reports +4 and feels healthy; the same studio is replacing 3.2 percent of its base every month — 38 percent a year — and paying acquisition cost on each replacement.
Replacement rate is the cost driver. At US$190 of cost per new member and 456 replacements a year, the studio spends US$86,000 a year to stand still; a studio with the same net change and half the churn spends US$43,000 and has the other US$43,000 as margin or growth.
How are cohort retention curves built and read?
A cohort is the members who joined in the same month. Tracked monthly: how many remain active one month later, two months, six, twelve; plotted as a curve, which in most studios drops steeply in months two through four — the trial-to-habit window — and flattens into a long tail of committed members; the shape of the curve is the studio's retention signature, and the business's job is to lift the early months.
Cohorts by acquisition offer and channel. Members who joined on a heavily discounted first month churn faster than those who paid full price; members from referrals stay longer than those from paid social; cohorts by offer and channel show which acquisition produces members and which produces churn — and the studio prices and markets accordingly.
Cohorts by membership tier and join season. Unlimited versus limited plans, annual versus monthly, January joiners versus September; each has its own curve, and the mix shapes the blended retention the studio reports.
What is the difference between voluntary and involuntary churn?
Voluntary churn is a decision to leave. Cancellation requests, freezes that become cancellations, non-renewals of annual plans; it responds to the member experience — class availability, instructor quality, community, results — and to the studio's cancellation friction, which is a retention lever with a reputational cost if overused.
Involuntary churn is a failed payment. Declined or expired cards, insufficient funds, bank changes; it can be a third of total churn and is largely recoverable with a dunning process — automated retries on a schedule, card-update prompts, a personal contact after the second failure, and a defined point at which the membership is suspended rather than silently lapsed; studios that install the process recover 35 to 55 percent of involuntary churn, which is often the single largest retention gain available.
How is lifetime value computed on a contribution basis?
Revenue per member per month, less the cost to serve them. Membership fee net of discounts and freezes, plus ancillary revenue — personal training, retail, add-ons — less the variable cost of serving the member: instructor cost per attendance, consumables, payment processing; summed over the months the cohort remains, discounted lightly for time; the result is lifetime contribution by cohort, which is the only honest denominator for acquisition cost.
The class-attendance link. Members who attend more stay longer; attendance in the first thirty days predicts retention at twelve months better than any demographic; the retention program is therefore an attendance program — onboarding sessions, booking nudges, a milestone at the fifth and tenth class — measured by first-month attendance by cohort.
How does cost per new member by channel decide acquisition spend?
Cost per new member is all acquisition spend divided by members who completed a first paid month. Paid social, search, referral bonuses, promotions and their discount cost, partnerships, events, and the staff time spent on tours and follow-up; by channel, using the source captured at join.
Payback is lifetime contribution against cost per new member. A channel producing members at US$140 with a lifetime contribution of US$520 pays back in about four months and should be scaled; a channel at US$310 producing a cohort worth US$260 is losing money on every member regardless of volume and should be cut or repriced; the decision is made channel by channel, and the discount cost of promotional offers is counted as acquisition cost.
What else belongs in the membership file?
Freezes and their economics. A freeze retains the member at reduced or no revenue; freeze-to-cancel conversion and freeze duration are tracked, and a freeze fee or cap is priced against the retention it preserves.
Annual and prepaid plans as deferred revenue. Annual memberships and class packs are liabilities recognized over the term or per class; breakage on class packs is recognized on a policy; and the cash from a January annual-plan promotion is read against the twelve months of service it bought.
Referral programs. Members referred by members retain best; the referral bonus is an acquisition cost with the lowest cost per new member and the highest lifetime value in most studios, which is why it is the channel to fund first.
Why is this CFO work?
Cohort curves require join, cancellation, freeze, and attendance data joined over time; the churn split requires payment-processor data read against the membership roll; lifetime contribution requires fee, ancillary, and variable-cost data by member; cost per new member requires acquisition spend attributed by channel with discount cost included; and the acquisition decisions are the owners' to make with payback in front of them. The studio's operators own the member experience; the CFO owns the economics that tell them which members, from which channels, on which offers, are worth acquiring.
Worked example
A four-studio boutique operator, US$4.6 million revenue, 2,850 members, US$11,000 a month of acquisition spend plus promotional discounts.
| Metric | Found | After twelve months |
|---|---|---|
| Monthly churn (total) | 6.9% | 4.3% |
| Involuntary share of churn | 31% | 14% (dunning recovery 48%) |
| Replacement rate (annual) | 83% | 52% |
| Cohort retention at month 4 — full-price joins vs. 50%-off first-month joins | 71% vs. 44% | 74% vs. offer withdrawn |
| Lifetime contribution — referral cohort vs. paid-social cohort | US$610 vs. US$240 | US$640 vs. US$310 |
| Cost per new member — referral vs. paid social (incl. discount cost) | US$90 vs. US$260 | US$95 vs. US$190 |
| Payback — paid social | 13 months (beyond cohort life) | 7 months |
| Acquisition spend | US$11,000 / mo + US$6,200 discount cost | US$7,400 / mo + US$1,100 discount cost |
| Members | 2,850 | 3,180 |
Illustrative figures for a hypothetical organization; not a client's data.
The operator had been increasing paid-social spend to hold the member count, acquiring members on a 50 percent first-month offer whose cohorts were gone by month four. The plan: dunning process installed; the discount offer withdrawn and replaced with a referral bonus; a first-30-day attendance program with a fifth-class milestone; paid social capped and retargeted to lookalikes of retained cohorts; annual plans moved to deferred revenue. Acquisition spend fell by a third, churn fell by more than a third, and the member base grew 12 percent on the same studios.