Method
How to judge a dupe in 30 seconds: the Twin Score method
"Is this a good dupe?" is usually answered with vibes in a comment section. Here is a way to answer it with a number, in the time it takes to scroll a product page.
RunwayTwin Journal · 7 November 2026 · 6 min read
RunwayTwin gives every alternative a Twin Score: 0–100, how close it gets to the original. It's an AI estimate, but the logic behind it is the same one a stylist uses, and you can run it in your head. Five tests, in the order a stranger's eye notices them.
| Test | Weight | What you check on the product page |
|---|---|---|
| 1. Silhouette | 30 | Length, volume, where it nips in, where the shoulder sits. Compare the model photo side by side with the original at the same crop. |
| 2. Fabric | 25 | Composition and weight. Look for the composition line and, for knits and coats, the weight (g/m²) or "heavyweight". |
| 3. Colour | 20 | In daylight photos, not studio renders. Black and white forgive; camel, cream, burgundy and metallics don't. |
| 4. Hardware & details | 15 | Buttons, buckles, zips, stitching, lining. Zoom to the largest photo; cheap hardware shines. |
| 5. Proportion on you | 10 | Sleeve and hem length for your height. A perfect dupe in the wrong length scores worse than a near one that fits. |
Score each test out of its weight and add them up. Under 50 is a different garment that shares a colour. 50–70 reads as "the same idea" across a room. 70–85 fools most people. Above 85 is rare away from basics, and usually means the original's maker also makes the cheaper one.
Weight the score by how much the piece matters
A belt at 50 and a coat at 50 are not the same failure. RunwayTwin weights each piece by visual weight (1–5): how much it defines the whole look. A coat or gown is a 4–5, a top under a jacket a 1–2. The look's Twin Score is the weighted average. In practice: be strict on the hero piece and relaxed on the rest.
The five fastest fails
- Polyester satin standing in for silk: it shines white, not soft, and clings.
- A blazer with narrow, padded shoulders when the original's are dropped and soft.
- Gold hardware that's yellow and mirror-bright rather than brushed.
- Knitwear in acrylic: it pills within weeks and loses the drape.
- Trousers cut to the ankle when the original pools over the shoe.
Check a product before you buy it
Open RunwayTwinQuestions
How do you know if a dupe is good?
Check five things in order of how visible they are: silhouette, fabric, colour, hardware and proportion on you. A dupe that gets the silhouette and fabric right will read as the original from a distance; one that only matches the colour won't.
What is a Twin Score?
RunwayTwin's 0–100 estimate of how close an alternative gets to an original piece or look, judged on cut, fabric, colour and details and weighted by how much each piece defines the look.
Cite this
RunwayTwin Journal, “How to judge a dupe in 30 seconds: the Twin Score method”, 7 November 2026. https://runwaytwin.com/blog/how-to-judge-a-dupe-twin-score