Cost Per Wash Calculator

Multiply the ounces of concentrate used per wash by the cost per ounce of concentrate. Cost per ounce is your cost per gallon divided by 128. For example, an 18-dollar-per-gallon presoak used at 3 oz per wash costs (18 ÷ 128) × 3 = about $0.42 per wash in chemistry.

Dema metering tips are color-coded plastic inserts used in Dema Engineering chemical proportioners and blend centers. Each color delivers a different ratio of concentrate to water, from roughly 1:512 (tan) to 1:8 (green) at 40 PSI inlet water pressure. Operators swap tips to change the dilution of a product without changing the chemistry.

A Dema Blend Center red tip meters chemistry at roughly 2 oz of concentrate per gallon of mixed solution, or about a 1:64 dilution ratio at 40 PSI water supply. Exact draw depends on water pressure, chemical viscosity, and line length — always verify against Dema's published chart for your specific model.

Self-serve bays typically use 15 to 30 gallons of water per wash. In-bay automatic tunnels average 35 to 50 gallons, and full conveyor tunnels can use 30 to 80 gallons depending on length and reclaim. Use your actual site data if you have it — water usage dramatically affects chemical cost per car.

Four levers: verify your metering tips match your chart so you're not over-applying chemistry, buy concentrates in larger containers (drums or totes drop the cost per gallon significantly), use products formulated to perform at higher dilution ratios, and train staff to mix accurately. Small changes in dilution compound across thousands of washes.

No. Chemical cost is usually only 10 to 25 percent of total per-wash cost. Water, sewer, labor, electricity, rent, and equipment depreciation make up the rest. This calculator focuses on chemistry so you can optimize that line item — you'll need a separate full-operation P&L for complete per-car economics.