Pressure Washer Calculator
Estimate how long a pressure washing job takes and how much water it uses.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
About this calculator
Estimate cleaning time from area, pass width, walking speed, overlap and passes. Water use includes spraying time only, not setup time. Surface, pressure, nozzle, soil and operator pace can change the result.
Worked example
calculated with the default values below
Area to clean 1,000 sq ft · Cleaning pass width 12 in · Your walking speed 20 ft/min · Washer flow rate 1.4 GPM · Overlap between passes 20 % · Number of passes 1 · Setup and packing away 15 minutes · Water price 6 $/1000 gal Area covered per minute 16.0 sq ft/min · Cleaning time 62.5 minutes · Total job time 77.5 minutes · Water used 87.5 gallons · Water cost 0.52 $ · Advice Reasonable pass width for a home job
Method and assumptions
C = (p ÷ 12)(1 − o ÷ 100) × v; T = A ÷ C × n + s; Q = T × f Effective pass width = pass width × (1 − overlap fraction); coverage = effective width × walking speed; cleaning time = area / coverage × passes. Water = cleaning time × flow rate, excluding setup time. This assumes uninterrupted spraying and steady pace. Estimate cleaning time from area, pass width, walking speed, overlap and passes. Water use includes spraying time only, not setup time. Surface, pressure, nozzle, soil and operator pace can change the result. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Data sources
The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Disclaimer
These calculators provide planning estimates only. Building codes, wiring regulations and safety requirements differ by country and change over time, and nothing here replaces a licensed professional or a permit. For structural, electrical or gas work, follow local code and have the installation inspected.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
C = (p ÷ 12)(1 − o ÷ 100) × v; T = A ÷ C × n + s; Q = T × f
- C
- Coverage rate (ft²/min)
- p
- Pass width (in)
- o
- Overlap (%)
- v
- Walk speed (ft/min)
- A
- Area (ft²)
- Q
- Water used (gal)
- T
- Total time (min)
- n
- Number of passes
- s
- Setup time (min)
- f
- Flow rate (gal/min)
Effective pass width = pass width × (1 − overlap fraction); coverage = effective width × walking speed; cleaning time = area / coverage × passes. Water = cleaning time × flow rate, excluding setup time. This assumes uninterrupted spraying and steady pace.
Frequently asked questions
Does the water estimate include setup time?
No. Water use is flow rate multiplied by estimated cleaning time. Setup time affects the total job duration but is not counted as active spraying.
Why does a wider cleaning pass reduce my total job time?
Coverage equals effective pass width, pass width minus overlap, times walking speed, so widening the 12-inch default pass from 12 to 24 inches nearly doubles area per minute even though the washer power is unchanged. At 20 ft/min with 20% overlap, a single pass covers about 16 sq ft/min, so 1,000 sq ft takes roughly 62 minutes plus your 15-minute setup.
Which inputs and limits apply to Pressure Washer Calculator?
Use the units shown beside each field. These are form limits, not recommended settings. Area to clean: 10–1,000,000 sq ft; Cleaning pass width: 1–60 in; Your walking speed: 1–300 ft/min; Washer flow rate: 0.1–10 GPM; Overlap between passes: 0–80 %; Number of passes: 1–5; Setup and packing away: 0–180 minutes; Water price: 0–200 $/1000 gal C = (p ÷ 12)(1 − o ÷ 100) × v; T = A ÷ C × n + s; Q = T × f Effective pass width = pass width × (1 − overlap fraction); coverage = effective width × walking speed; cleaning time = area / coverage × passes. Water = cleaning time × flow rate, excluding setup time. This assumes uninterrupted spraying and steady pace. Estimate cleaning time from area, pass width, walking speed, overlap and passes. Water use includes spraying time only, not setup time. Surface, pressure, nozzle, soil and operator pace can change the result. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
What is a complete worked example for Area to clean = 1,000 sq ft; Cleaning pass width = 12 in?
Inputs: Area to clean = 1,000 sq ft; Cleaning pass width = 12 in; Your walking speed = 20 ft/min; Washer flow rate = 1.4 GPM; Overlap between passes = 20 %; Number of passes = 1; Setup and packing away = 15 minutes; Water price = 6 $/1000 gal. Calculation: C = (p ÷ 12)(1 − o ÷ 100) × v; T = A ÷ C × n + s; Q = T × f. Results: Area covered per minute = 16.0 sq ft/min; Cleaning time = 62.5 minutes; Total job time = 77.5 minutes; Water used = 87.5 gallons; Water cost = 0.52 $; Advice = Reasonable pass width for a home job.