Step 1 — What do you need to clean?
Check every task that applies. The calculator will recommend based on your highest-demand task.
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Pressure Washer PSI Guide: What You Need to Know
Choosing the right pressure washer comes down to one key question: how much cleaning power does your job actually require? Buy too little and you'll be scrubbing anyway. Buy too much and you risk damaging delicate surfaces like car paint, soft wood, or window seals.
What Does PSI Mean on a Pressure Washer?
PSI (pounds per square inch) measures how forcefully the water hits the surface. Higher PSI = more force = better for tough grime on hard surfaces. But it also means a higher risk of damage on softer materials.
GPM (gallons per minute) measures how much water flows. More GPM means you flush away loose debris faster. Serious cleaning power is actually PSI × GPM — called Cleaning Units (CU). A 2500 PSI / 2.0 GPM machine has 5,000 CU, which cleans significantly faster than a 2500 PSI / 1.2 GPM machine.
Electric vs. Gas Pressure Washers
Electric models are quieter, require less maintenance, start instantly, and are great for light-to-medium duty tasks around the home. Modern brushless motor electrics now rival gas in PSI output.
Gas models offer more raw power and mobility (no cord), making them better for heavy-duty concrete work, large areas, and jobs far from an outlet. They require oil changes and spark plug maintenance.
Quick PSI Reference Table
| Task | Recommended PSI | Tier |
|---|---|---|
| Car / motorcycle | 1,200 – 1,900 PSI | Light Duty |
| Patio furniture / grill | 1,300 – 1,800 PSI | Light Duty |
| Windows / bikes | 1,300 – 1,600 PSI | Light Duty |
| Wood deck | 1,500 – 2,500 PSI | Medium Duty |
| House siding / fence | 1,800 – 2,500 PSI | Medium Duty |
| Mold & mildew removal | 2,000 – 2,500 PSI | Medium Duty |
| Concrete driveway | 2,500 – 3,200 PSI | Heavy Duty |
| Brick / stone | 2,500 – 3,000 PSI | Heavy Duty |
| Oil stains / tough grime | 2,800 – 3,200 PSI | Heavy Duty |
| Paint stripping | 3,000 – 4,000 PSI | Extra Heavy |
| Large commercial areas | 3,300 – 4,000+ PSI | Extra Heavy |
Tips for Getting the Best Results
- Use the right nozzle. A 0° (red) nozzle is for spot stripping. A 25° (green) nozzle is all-purpose. A 40° (white) nozzle is for delicate surfaces and rinsing.
- Keep the wand moving on wood. Holding in one spot will etch or fuzz the grain. Work with long, even strokes.
- Pre-soak tough areas. Let a detergent dwell for 5–10 minutes before rinsing concrete or siding — it does much of the work.
- Start far, move closer. Begin at 2–3 feet away and move in until the cleaning action is what you need. Safer and protects surfaces.
- Never point at people, pets, or glass. Even "light duty" pressure washers can cut skin or shatter a window at close range.