Pressure Washer Time Estimate Calculator
Estimate how long a pressure-washing job takes from the area, how dirty the surface is and the number of passes.
How it works
Wash time = area × passes ÷ cleaning rate · Total = wash time + setup
Pressure-washing speed depends far more on how dirty a surface is than on the machine’s peak pressure. Light dust rinses off at roughly 6 ft² a minute, ordinary grime and algae slow you to about 3.5, and caked moss, oil or mildew that needs slow, close passes drops to 2 or less. Multiply the area by the number of passes (many jobs want a detergent pass plus a rinse), divide by the rate, then add setup — hooking up the hose, mixing detergent and packing away easily eats 15 minutes on top.
Worked example
A 500 ft² driveway with moderate grime at 3.5 ft²/min, cleaned in a single pass: 500 ÷ 3.5 = 143 minutes ≈ 2 hr 23 min of washing. Adding 15 minutes of setup and pack-up gives about 2 hr 38 min for the whole job.
Frequently asked questions
Does a more powerful washer clean faster?
Up to a point. Higher flow (GPM) matters more than peak pressure (PSI) for speed, because flow rinses debris away. But the surface condition dominates — no machine turns heavy moss removal into a quick rinse.
Why add a second pass?
Most real jobs are two passes: a detergent or degreaser pass that dwells and lifts the grime, then a rinse pass. Set passes to 2 for anything with mildew, algae or oil rather than a light dusting.
How do I speed up a big job?
Use a surface cleaner attachment for flat areas like driveways and patios — its spinning bar covers a wide, even strip and can double or triple your ft²/min compared with a single wand tip.
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This calculator is for educational purposes. Double-check important results before acting on them.