Methodology
Transparent assumptions, editable rates.
Every calculator on this site estimates labor hours, job duration, direct cost, overhead, and a target price from values entered by the visitor.
Labor hours
Labor hours = (area / production rate) × condition multiplier + setup time
Production rate represents the area one operator's equipment covers in one hour at normal working speed. The default rates are broad starting benchmarks pulled from published industry pricing guides. Operators should replace them with rates measured from their own completed jobs.
Loaded labor cost
Base wages = labor hours × hourly wage
Loaded labor cost = base wages × (1 + labor burden)
Labor burden may include employer payroll taxes, workers' compensation, unemployment insurance, benefits, and other employee-related costs above base wage.
Direct cost, overhead, and margin
Direct cost = loaded labor cost + chemicals + equipment/fuel/water
Break-even cost = direct cost + (direct cost × overhead rate)
Price = break-even cost / (1 - target profit margin), or the job minimum, whichever is higher.
Margin and markup are different. The calculator uses profit margin as a percentage of the final price, not a markup on cost.
Important limitations
The result is a planning estimate. It does not automatically include permits, specialty insurance riders, financing, warranty callbacks, or every local runoff or wastewater regulation. Verify every job before submitting a bid.
Formula transparency
What the calculator does not assume for you
The calculator does not decide whether a surface can safely take pressure, whether a job is code-compliant, or whether the price is competitive in your market. It organizes the math so an operator can review the assumptions. Users should still verify surface material, water source and drainage rules, insurance requirements, and local pricing.
Default values are examples, not universal rates. An operator working with a hot water unit, in a high-cost market, or on a specialty surface should replace the defaults with known business costs. The goal is not to produce a magic price; the goal is to make the estimate easier to audit before it becomes a customer-facing number.
Worked formula example
Example driveway calculation
Assume a 1,200 sq ft concrete driveway with moderate staining (a 1.3 condition multiplier), a 1,500 sq ft/hr production rate, and 25 minutes of drive and setup time. Labor hours are (1,200 / 1,500) × 1.3 + (25 / 60), or about 1.46 hours.
If the base wage is $24 per hour and labor burden is 20 percent, loaded labor cost is $28.80 per hour. About 1.46 hours at $28.80 per hour is roughly $42 in loaded labor cost. Adding $18 in chemicals and $22 in equipment, fuel, and water brings direct cost to about $82. At 15 percent overhead, that adds about $12, bringing break-even cost to about $94. At a 25 percent target margin, the price is $94 / 0.75, or about $126 — above the $125 job minimum, so the calculated price applies rather than the floor.
This example explains why the calculator separates wage, burden, chemicals, equipment, overhead, and profit. An operator who only multiplies square footage by a flat per-foot rate may send a price that covers labor but not the real chemical, equipment, and overhead cost behind the job.
Step-by-step
The six steps behind every number this calculator produces
The formulas above are the reference version. In practice, operators walk through them in a fixed order, and skipping a step is the most common way a bid ends up wrong.
- Measure the surface area on site. Street-view estimates of a driveway or roof are frequently off by 15 percent or more once actually measured.
- Rate the staining or growth severity honestly. Light, moderate, and heavy are not marketing labels — they change dwell time, pass count, and sometimes the chemical mix itself.
- Divide by your own production rate. Published benchmarks are a starting point. Your equipment, nozzle setup, and experience change the real number.
- Add setup and access time. Water source distance, ladder or roof-access setup, and drive time all belong here, not folded invisibly into a lower production rate.
- Use loaded labor cost, not base wage. Payroll taxes, workers' compensation, and benefits can make a $24 wage cost the business meaningfully more than $24 an hour.
- Add chemicals, equipment, overhead, and profit last. These are real per-job costs, not incidental extras, and profit is what's left after every other cost is covered.
A quick check on the math: 1.46 labor hours at a $24 wage is about $35 in base wages. With 20 percent labor burden, loaded labor cost is about $42. Chemicals, equipment, overhead, and margin still need to be added on top of that before the number becomes a bid — see the worked example above for the complete build-up.