Car Wash Payback Calculator
A car wash sells single washes and monthly memberships. Enter the paid washes, the membership base, the costs and the loan, and the calculator returns the wash's cash flow, its debt service coverage and how long it takes to pay back.
The calculator
This calculator runs in your browser. Nothing you type is sent anywhere or kept: no network request, no cookie, no storage. Results update as you type.
Your inputs
Results
- Single-wash revenue
- Membership revenue
- Revenue, per year
- Operating expenses, per year
- Net operating income (cash flow before debt service)
- Monthly loan payment
- Annual debt service
- Debt service coverage
- Cash flow after debt service, per year
- Equity in (project cost less the loan)
- Simple payback on the project cost
- Payback on the equity
- Cash-on-cash return on the equity
- Break-even revenue (covers operating expenses and debt service)
- Revenue cushion (how far revenue can fall before cash flow after debt service reaches zero)
A field left empty counts as not entered, and the results that need it read "not computed"; fields that say "Leave empty for none" count as zero.
What it computes, and the formulas
The calculator builds a year's revenue from the car wash lines below, takes off the operating expenses, and sets the net operating income against the loan: the coverage a lender reads, the cash left after the payments, and the years the project and the equity take to pay back. A break-even line shows how far revenue can fall before the cash flow after debt service reaches zero.
- Revenue: the sum of the lines. Single-wash revenue = washes per day × days open × revenue per wash; Membership revenue = members × monthly price × 12.
- Operating expenses: E = revenue × the share that rises with revenue + fixed expenses.
- Net operating income: NOI = revenue − E.
- Monthly payment on a loan L: P = L × r ÷ (1 − (1 + r)−n), with r = annual interest rate ÷ 12 and n = amortization in years × 12 (at a zero rate, P = L ÷ n). Annual debt service: D = 12 × P.
- Debt service coverage: NOI ÷ D. Cash flow after debt service: CF = NOI − D.
- Equity: total project cost − L.
- Simple payback on the project cost: total project cost ÷ NOI, in years.
- Payback on the equity: equity ÷ CF, in years. Cash-on-cash return: CF ÷ equity.
- Break-even revenue: (fixed expenses + D) ÷ (1 − the share that rises with revenue). Revenue cushion: 1 − break-even revenue ÷ revenue.
A payback that never arrives, because the net operating income or the cash flow after debt service is not positive, reads "never at these inputs". For coverage and the largest loan the cash flow carries, use the DSCR and Loan Sizing Calculator.
Entering a car wash project
Members pay a monthly price for unlimited washes, so their visits stay out of the single-wash count and their revenue is the membership line. Chemicals, water, electricity and card fees rise with volume and belong in the variable share; staff, equipment maintenance, property taxes, insurance and marketing are mostly fixed.
An express tunnel's cash flow rests on its membership base, which takes time to build after opening and can fall when a competitor opens nearby. Test the wash with fewer members and a lower single-wash count, and enter the conveyor, dryers and pay stations in the project cost.
What it does not do
- An estimate, not a feasibility study: it takes your revenue and costs as given and tests none of them against a market, a trade area or the competition.
- Not an appraisal: it states no value for the property or the business.
- Not lending advice: a lender sizes a loan on its own credit policy, its program's rules and its own reading of the cash flow.
- One stabilized year, undiscounted: no ramp-up, no growth in prices or costs, no inflation, no income tax, no depreciation, no sale and no change in value. Payback counts years of that steady cash flow, and a later dollar counts the same as a dollar today.
- One loan, fully amortizing in equal monthly payments at a fixed rate: no interest-only period, balloon, fees or second lien. An SBA 504 project carries two liens, and its coverage is tested on both payments together.
The method behind these tests is set out in the methodology series: Sensitivity and Stress Testing: Break-Even Points, Shock Sizes and What a Lender Should See.
Worked example
The inputs below are illustrative, chosen to show the arithmetic for a car wash project. They are not data, not typical values and not a forecast for any site.
Every example finances at 9.25 percent over 25 years, the rate and term of the illustration in the methodology article on debt service coverage; enter the terms your lender quotes instead.
| Paid single washes per day, on average | 180 |
|---|---|
| Days open per year | 340 |
| Average revenue per single wash | $14 |
| Monthly members, on average | 1,500 |
| Membership price per month | $30 |
| Operating expenses that rise with revenue, as a share of revenue | 12% |
| Fixed operating expenses, per year | $560,000 |
| Total project cost | $5,500,000 |
| Loan amount | $4,400,000 |
| Interest rate, per year | 9.25% |
| Amortization | 25 years |
| Single-wash revenue | $856,800 |
|---|---|
| Membership revenue | $540,000 |
| Revenue, per year | $1,396,800 |
| Operating expenses, per year | $727,616 |
| Net operating income (cash flow before debt service) | $669,184 |
| Monthly loan payment | $37,681 |
| Annual debt service | $452,170 |
| Debt service coverage | 1.48x |
| Cash flow after debt service, per year | $217,014 |
| Equity in (project cost less the loan) | $1,100,000 |
| Simple payback on the project cost | 8.2 years |
| Payback on the equity | 5.1 years |
| Cash-on-cash return on the equity | 19.7% |
| Break-even revenue (covers operating expenses and debt service) | $1,150,193 |
| Revenue cushion (how far revenue can fall before cash flow after debt service reaches zero) | 17.7% |
SBA 7(a) and 504 loan record for car wash
| Program | Loans approved | Median loan | Charged off (floor) | Charged off within five years (floor) |
|---|---|---|---|---|
| SBA 7(a) | 2,713 | $789,000 | 2.5% | 1.5% |
| SBA 504 | 997 | $1.1 million | 1.00% | 0.75% |
Both charge-off columns are floors: SBA withholds the status of open loans, so a loan counts as charged off only once SBA reports it, and a rate needs at least 30 loans in its cohort and is otherwise not reported. How the floor is built: The Approval-Cohort Charge-Off Floor: Why a Published SBA Loss Rate Can Only Understate.
Car and truck washes, including mobile washes, share one code. Shared code: Truck washes share 811192.
Source: U.S. Small Business Administration, 7(a) and 504 loan-level FOIA files (data.sba.gov), as of 2026-09-30; Loan Analytics loan-outcome cells PA-C02-7A, PA-C02-504.
Cite this calculator
Loan Analytics. "Car Wash Payback Calculator." https://www.analytics.loan/tools/car-wash-payback-calculator. SBA loan data as of 2026-09-30; page built 2026-11-10.
Methodology
- Sensitivity and Stress Testing: Break-Even Points, Shock Sizes and What a Lender Should See
- The Loan Analytics methodology series
Car Wash feasibility study pages
SBA program pages
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