Short format. The company is a fictional medical aesthetic cosmetics chain (5 clinics in Kyiv); the economics are assembled from real Ukrainian sources for 2026 and documented in the primary sources registry. Full analysis in the deep dive, the model itself is here.
I built the model together with an AI tool (Claude) — but I decided which metrics to calculate and why. Crucially: instead of taking an “average receipt” out of thin air, I split it into 5 service lines (injections, devices, care, laser, diagnostics), took prices from the real price list of a direct analogue (Slim, slim.ua) and weighted them by each line’s share in visits — the result is ₴4,228, and this is visible in the table above the calculator. Each parameter has a reliability grade A/B/C and a source tag [S]/[M]/[D]; where Ukrainian data were missing, I kept international benchmarks with transparent labelling. The AI helped quickly assemble an interactive calculation and format it. But the logic — why we calculate LTV by margin not by receipt, why response speed in DMs moves the whole economics so much — I analysed and validated myself. I specifically made a “slow / fast response” comparison because it's the most practical takeaway for a real business. Using AI as a tool is fine, like previously using Excel; what's important is that I understand what lies behind the numbers, not who drew the slider.
CAC (Customer Acquisition Cost) — how much one customer from targeted ads costs. We divide the paid budget by the number of people who actually arrived after the funnel: lead → booking → first visit. By default ≈ ₴1,800. But 58% of customers come not from targeting — so the blended CAC ≈ ₴940.
The receipt ₴4,228 is the customer's money. Injection products eat 30–50% of the receipt, the doctor's bonus is a % of the remainder, plus an allocated share of rent and salaries for that visit. For LTV we take gross margin ≈44% (not contribution margin ~62% — because a repeat customer occupies the room and staff the same). Calculating LTV by receipt would overstate it nearly twofold.
The ratio of “how much a customer brought” to “how much it cost to acquire them”. The “minimum 3x” threshold comes from the venture world; the logic is universal: you need a buffer for rent, salaries, contingencies. In LUMÉ it comes out ≈ 9.8x (paid channel) and ~21x (blended) — and this is not “everything is perfect”, but a signal: money should be invested not in ads, but in capacity (rooms at 76%, the network near ceiling) and retention. A junior might say “increase the budget” — that is a mistake.
No. Prices are from real Kyiv clinic price lists (Slim as a direct analogue, plus Bellezza, NeoVita, Laserhouse, Dr.Yudina). The macro series 2021–2026 (GDP, inflation, exchange rate, real wages) — State Statistics Service/NBU, grade A. Taxes, MOH licence — official sources, grade A. Beauty inflation for 2025 (Barb.ua estimate [M]; official medical CPI +6%), injection cosmetology Kyiv +40% for 2023 — Barb.ua/Forbes/OstroV. Visit frequency (8–12/year), retention (70%+), share of injections in revenue (50–70%) — from real guides business-broker.com.ua and cms.beauty (run 10 of the registry, 08.09.2026). CPL Meta ₴620 — grade C (triangulation). Exchange rate ₴44.5/$ — NBU on 8 September. What is NOT closed: the exact mix of visits by line, an independent financial anchor from real networks (YouControl registries), market volume in ₴ — honestly marked [M].
No, it's normal for a service with repeat visits. In the first month you pay for acquisition, and the profit from a customer is spread over future visits. You should judge by LTV, not by the first month.
LTV:CAC answers “is it profitable in principle”, payback answers “how quickly will the money return”. A campaign can be profitable by ratio but have an 18‑month payback — and then there's no way to finance it with limited cash.
In the “slow” scenario, lead → booking conversion drops (38%→18%) and the share of “regulars” falls (42%→30%). An anxious client with an expensive procedure (injection visit ≈₴7,800) goes to whoever calmly replied first. The effect is supported by a study of 100,000+ leads (Oldroyd/HBR): 5 minutes instead of 30 = 100× chance to reach them. One operational process (SLA ≤1 min) moves the economics more than any budget change — and budget in the model is already not the main lever.
In the model — almost nothing (conversion percentages). In reality CAC increases — cheap audiences burn out first. The model does not account for this — an honest limitation. But since LTV:CAC ≈ 8x, the bottleneck is not the budget but capacity and retention — so it's not critical.
Splitting the receipt into 5 service lines (not “one number out of thin air”), a two‑segment customer model (regulars / non‑regulars), a season toggle, blended CAC across channels, cohort retention curve by years, market retrospective 2021–2026 on a real macro series, and a tornado analysis — which lever moves LTV:CAC the most (it turned out — not budget, but the share of regulars and their visit frequency).