Pressure Washing Calculator

Recommended PSI is set purely by Surface Type -- it reflects what pressure a given material can safely tolerate, not how much of it you're cleaning. A small patch of vinyl siding and a large one both call for the same lower PSI, because the risk of damage comes from the pressure itself, not the total area.

Area, for a fixed surface type and soil level -- doubling the square footage roughly doubles the time at whatever cleaning rate that surface and soil combination produces. But Surface Type and Soil Level are not separate from the time calculation: they set the cleaning rate itself, and switching between them can swing Estimated Time by several times over even with Area held constant, so all three inputs genuinely drive how long a job takes.

Vinyl siding is a much softer, more damage-prone material than concrete -- excessive pressure can crack panels, drive water behind them, or strip the finish. Concrete can tolerate roughly twice the PSI that vinyl siding can, which is why this calculator recommends 1,300 PSI for siding versus 3,000 PSI for concrete.

Heavier soiling slows the effective cleaning rate -- more passes or dwell time are needed to lift ground-in grime -- which increases Estimated Time for the same area, and it also raises both the detergent concentration and the per-square-foot cost multiplier used in Estimated Cost.

Treat it as a starting point, not a guarantee. This calculator gives a typical safe PSI by surface category, but real-world safety also depends on nozzle tip angle, standoff distance, and the surface's actual condition -- aged wood, already-cracked concrete, or worn siding can be damaged at pressures that would be fine on new material, so always test on an inconspicuous area first.