Express Car Wash Acquisition & Membership Financial Model — Membership Penetration Engine (Excel + Google Sheets)

Buying a single express car wash with SBA financing — and need to know whether the deal actually covers its debt? Every other car-wash template makes you type a guessed monthly revenue and ignores the one thing that decides value: how much of it recurs. A car wash lives or dies on its membership base. So this model builds your revenue from a membership engine instead.

It models your member base the way it actually behaves — a stock that fills with sign-ups and drains with churn — around one signature identity: steady-state members = monthly sign-ups ÷ monthly churn. From that base it builds recurring membership revenue (members × ARPM × 12), adds one-off retail, and shows the number a buyer and a lender anchor on: your membership penetration, the share of revenue that recurs. Then it underwrites the purchase like an SBA acquisition — enterprise value, capital stack, DSCR, the unlevered yield, cash-on-cash, payback and a 5-year exit.

What it builds for your deal:

• Membership Penetration Engine — steady members = adds ÷ churn, with tenure (1 ÷ churn) and gross LTV (ARPM ÷ churn). Move churn, sign-ups or ARPM and the whole base, the revenue and the penetration recompute. The default settles at 2,733 members, 72.7% penetration and a 13.3-month tenure.
• Variable cost done right — the cost rides on the washes members actually take (2.6/month), not the flat price they pay. Over-washing shows up where it should: in the margin. The trap that sinks naive car-wash models, fixed.
• 3-wash-type toggle — one switch reloads the whole economics (ticket, ARPM, sign-ups, throughput, labour, multiple) from an editable preset table: Express Exterior, Flex Serve and In-Bay Automatic all in one file.
• Year-1 cash runway — see how the recurring base smooths the seasonal dip that sinks retail-only washes, month by month, while the SBA note is due.
• 5-year P&L, EBITDA & SDE — EBITDA struck after a market owner/GM wage, SDE added back, at SITE level (explicitly not the corporate margin). The default runs $1,264,000 revenue at a 50.0% site EBITDA margin.
• Full SBA underwrite — enterprise value at your multiple ($3.58M at the default 5.5x), the capital stack, DSCR 1.97x, an 18.2% unlevered EBITDA yield, cash-on-cash, a 2.58-year payback and a conservative 5-year exit.

What's inside:

• 10-sheet Excel workbook (works in Google Sheets too — no macros, no add-ins, no external links)
• 18-page PDF user guide — quick start, sheet-by-sheet walkthrough, how the membership engine works, how a lender reads your DSCR, unlevered yield and payback, where to find the seller's real numbers, and a full FAQ
• START HERE sheet: your first underwrite in minutes, only amber cells to fill
• Membership Engine sheet — steady members = adds ÷ churn, with tenure and LTV
• Setup sheet with a 3-wash-type preset matrix you can edit to your exact site
• Dashboard with KPI cards and a 5-year revenue-vs-EBITDA chart, formatted to share with a lender or partner
• Benchmarks sheet with sourced 2024-26 penetration, churn, ARPM, multiples, DSCR and SBA-term ranges

Why this one: every formula is machine-verified — the full calculation graph is recomputed by three independent engines (including Excel itself) before release, and the membership engine, the wash-type toggle and the SBA underwrite are all stress-tested. Honest by design: the headline is penetration, DSCR and the unlevered yield, not a cash-on-cash flattered by leverage. Models that balance.

Educational planning tool — not financial, legal, tax or investment advice. Car-wash pricing, churn, ARPM, multiples and utility costs vary by market and change over time; validate the seller's financials, your SBA terms and local water/utility costs before relying on any number.