Every dishwasher gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Dishwashers are grouped by type (countertop and portable) and use the same scale in both.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per place setting | 35% |
| Capacity | place settings per load | 15% |
| Water use | gallons per cycle | 15% |
| Noise | the maker's rated sound level | 10% |
| Convenience | a built-in tank that needs no plumbing, and heated drying | 25% |
Where the numbers come from
Place settings, programs, water per cycle, noise, annual energy, dimensions, weight and warranty come from the maker’s product page, manual or help center, the ENERGY STAR product finder, or the Amazon listing where none of those states it. Each value’s source is noted on its product page. Prices are Amazon prices for a new item. Anything a maker doesn’t publish is left blank rather than taken from a review site. A maker that gives only an item count, such as “30+ items”, gets no place-setting count.
The factors
Value is the current price divided by the published place settings, on a log scale, so halving the price per setting always counts the same. $110 per setting scores zero and $30 per setting full marks.
Capacity is the place settings per load: 3 scores zero and 10 full marks.
Water use is the gallons per cycle the maker or the ENERGY STAR certification states (the ENERGY STAR figure where a model is certified, so certified models share one test basis), with 4 gallons scoring zero and 0.7 gallons full marks. Liters are converted to gallons. For tank models, the tank fill counts only where the maker states it as the use per cycle.
Noise is the maker’s rated sound level: 62 dB scores zero and 40 dB full marks.
Convenience adds two features: a built-in tank that runs with no faucet hookup (60% of the score) and heated or hot-air drying (40%). A model with a faucet hookup only and no stated drying scores zero here, and a model whose drying isn’t stated is marked estimated.
What isn’t scored
Programs, ENERGY STAR status, annual energy, dimensions, weight and warranty are listed but not scored. Annual energy and ENERGY STAR status are published for too few models to compare, and nearly every model carries a one-year warranty. No independent testing has been published for these models, so cleaning performance isn’t scored.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Many tank-style models don’t state place settings, so their value and capacity factors are estimated.
What isn’t ranked
Built-in and undercounter dishwashers, drawer dishwashers, commercial dishwashers, sterilizer cabinets, ultrasonic cleaners and parts aren’t ranked. Models with no usable photo or in-stock store are held back until one turns up.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.