1. The premium spec sheet is the reference
Every category has a short list of specs that decide whether a product is good at its job: bowl size and motor for a stand mixer, suction and run time for a cordless vacuum. Each spec gets a weight from 1 to 3 for how much it matters. Some specs are shown for information only and never scored, such as pump pressure on espresso machines, where a higher number is not better.
We only score against specs the premium maker actually publishes. If the premium brand keeps a number secret, that spec is removed from the calculation entirely, so no alternative is punished for the premium brand's silence.
Where a maker publishes no figure but the product's exact Amazon listing states one, we use the listing's figure and mark it with A. It is read from the listing's title, bullet points and details by software each time the listing is refreshed, it never replaces a figure the maker publishes, and it disappears with the listing once that is more than a day old. A listing that turns out to be a bundle, an accessory or a different size contributes nothing.
2. Each alternative is scored spec by spec
- Numbers where more is better (capacity, warranty): matching or beating the premium figure earns full credit; falling short earns a proportional share. A 4.5 qt bowl against a 5 qt bowl earns 90%.
- Numbers where less is better (weight): the same, inverted.
- Yes/no features (attachment hub, lifetime warranty): full credit if the alternative has it, none if it does not.
- Types (forged vs stamped): full credit for the same type, none otherwise.
- Not listed by the alternative's maker: 50% credit. Unproven is not the same as missing, but it is not a match either.
The DupeScore is the weighted credit earned divided by the weighted credit available, from 0 to 100.
3. Thin comparisons are not published
An alternative only appears on a page when its maker lists at least 50% of the weighted specs we are comparing, and when it scores at least 40. Below that, a score says more about missing data than about the product. Ranked lists for a single spec (for example "longest warranty") only exist when at least two alternatives publish that spec.
A worked example
The KitchenAid Artisan 5 Qt Tilt-Head against the Instant Stand Mixer Pro 7.4 Qt:
| Spec | KitchenAid Artisan | Instant Stand Mixer Pro |
|---|---|---|
| Bowl capacity | 5 qt | 7.4 qt |
| Motor power | 325 W | 600 W |
| Speed settings | 10 | 10 |
| Warranty | 1 yr | 1 yr |
| Attachment power hub | Yes | Yes |
| Head style | Tilt-head | Tilt-head |
| Weight | 22.8 lb | Not listed |
Result: 96, with 92% of the scored specs published by both makers. See the full page.
4. Prices
Prices are the maker's own list price, or a named retailer's where the maker does not show one, with the date we checked. Where we could not verify a price we show a price band instead. Savings and rankings always use that list price, never a shop's current price, so a sale cannot move a product up the map. Where we have matched the exact Amazon listing, the button also shows Amazon's current price from Amazon's product API, with the time it was fetched; it is refreshed every few hours and hidden once it is more than a day old.
5. What a DupeScore is not
It is not a review, a rating or a test result. We have not used these products. A spec sheet cannot tell you about build quality, noise, reliability or how a knife feels in the hand. Use the score to shortlist, then read hands-on reviews before you buy.
6. Corrections
Makers change specs and discontinue models. If you spot a wrong number, email us with a link to the maker's page and we will fix it; the page's "updated" date changes when we do.