How we rank products

Every ranking on this site is calculated, not hand-picked. Here is the whole method.

1. Specs come from the manufacturer

We enter only figures the manufacturer publishes and link the page we used under every product. If a figure isn't published we show "Not listed" instead of guessing.

2. Each spec is scaled from 0 to 1

Each criterion has a fixed reference range, from a "weakest reasonable" value to a "best in class" value (for example 1,000 to 7,000 running watts for portable inverter generators). A product's figure is placed on that range and clamped between 0 and 1, so scores stay meaningful as products are added. For specs where lower is better, such as weight, the range runs the other way. Yes/no features count as 1 or 0. The ranges are listed below.

3. Weights decide what matters most

Each category lists its criteria and weights on the page. The score is the weighted average, multiplied by 10:

score = 10 × Σ(weight × scaled value) ÷ Σ(weight)

4. How missing data is scored

If a spec isn't published (for example a rated motor figure when the maker prints only peak watts), the product scores at the lowest value any product in that category actually published, so an unpublished figure never outranks a published one. The page marks each such cell with an asterisk. Yes/no features that aren't stated count as no. Nothing is ever scored at the category average.

5. Prices and ratings switch on automatically

When our retailer feeds supply a current price or customer rating for at least 60% of products in a category, two more criteria join the formula: Price / value (20%) and Customer rating (15%, discounted when there are few reviews). Until then we show "Check price" and never estimate a price.

6. What the score can't tell you

Specs don't capture power quality under real loads, reliability, ease of starting or dealer support. Runtime and noise are each maker's own claims, measured at a load and distance it chooses; we note the basis where it's stated. Cleaning units for pressure washers are PSI × GPM, which we multiply ourselves and label as computed. Generator output is ranked on running (rated) watts, not peak watts. Nothing here is legal advice. Use the score to shortlist, then read the pros, cons and sources. When we add hands-on testing notes, we label them clearly.

7. Money never changes the order

We earn affiliate commissions from some retailers. Commission rates are not an input to the formula, and no brand can pay for placement. See our affiliate disclosure.

Criteria by category

Portable Inverter Generators

• Running watts (gasoline): 25% · range 1000 → 7000 W
• Runtime at 25% load: 15% · range 5 → 20 h
• Runtime at 50% load: 5% · range 4 → 12 h
• Noise: 15% · range 70 → 50 dBA
• Weight: 10% · range 220 → 35 lb
• CO shutoff: 10% · yes/no
• Runs on propane: 10% · yes/no
• CARB compliant: 5% · yes/no
• Parallel capable: 5% · yes/no

Dual-Fuel & Open-Frame Portable Generators

• Running watts (gasoline): 25% · range 3000 → 10000 W
• Starting watts: 5% · range 4000 → 12500 W
• Runtime at 50% load: 15% · range 6 → 14 h
• Runtime at 25% load: 5% · range 8 → 25 h
• Noise: 10% · range 82 → 65 dBA
• Transfer-switch ready: 10% · yes/no
• CO shutoff: 10% · yes/no
• Runs on propane: 10% · yes/no
• Weight: 5% · range 240 → 100 lb
• CARB compliant: 5% · yes/no

Home Standby & Large Portable Generators

• Running watts (best listed fuel): 35% · range 8000 → 26000 W
• Noise: 15% · range 85 → 55 dBA
• Runs on natural gas: 15% · yes/no
• Runtime at 50% load (gasoline): 10% · range 6 → 14 h
• Transfer switch / transfer-switch ready: 10% · yes/no
• CO shutoff: 10% · yes/no
• CARB compliant: 5% · yes/no

Electric Pressure Washers

• Pressure (max listed): 30% · range 1700 → 3400 PSI
• Flow (max listed): 25% · range 1.1 → 2.3 GPM
• Cleaning units (computed): 20% · range 1500 → 6500 CU
• High-pressure hose length: 10% · range 20 → 35 ft
• Brushless or induction motor: 10% · yes/no
• Weight: 5% · range 70 → 13 lb

Gas Pressure Washers

• Pressure: 30% · range 2800 → 4400 PSI
• Flow: 25% · range 2 → 4.2 GPM
• Cleaning units (computed): 20% · range 5800 → 18500 CU
• High-pressure hose length: 10% · range 25 → 50 ft
• Triplex pump: 10% · yes/no
• Weight: 5% · range 145 → 50 lb