iPhone Duo vs iPhone 18 Pro Max: which one should you buy?
A practical comparison of screen size, cameras, battery and price to help you choose between the foldable and the biggest slab iPhone.
"Should I get iPhone Duo or the 18 Pro Max?" is one of the most common questions since launch. The short answer: the Duo is the better screen, the Pro Max is the simpler phone. Here is how that plays out.
Screen: the biggest difference
Apple says the Duo's 7.6-inch inner display is 50 percent larger than the iPhone 18 Pro Max display, and that its outer display has more than 90 percent of the screen area of iPhone 18 Pro. So closed, you get roughly a normal iPhone; open, you get a small tablet. If you read, edit, watch video or use two apps side by side, that matters every day. See our screen size guide.
Shape and pocket
The Duo is 11.3 mm thick closed and 5.2 mm open, at 254 grams. It is narrower in the pocket than a Pro Max-class phone but thicker. If you hate thick phones, that is the trade.
Cameras
The Duo has two 48MP rear cameras: Fusion Main and Fusion Ultra Wide, with 2x optical-quality zoom from the main sensor. There is no dedicated long telephoto listed on its spec sheet, so if you shoot distant subjects often, a Pro model is the safer bet. What the Duo adds is the outer display as a viewfinder for the people you photograph: Duo Preview, Kid Cue and Smart Take. Read our Duo vs Pro camera comparison for the details.
Unlock and security
The Duo uses Touch ID in the side button, not Face ID. Some people prefer it, some do not. It is worth trying in a store.
Price
iPhone Duo starts at $1,999 in the US. Check our US, Canada and UK pricing guide and the trade-in and carrier deals guide before deciding.
Who should buy which
- Choose iPhone Duo if you read, multitask, edit photos or record yourself and want a bigger canvas.
- Choose a Pro Max if you want the longest zoom, Face ID and a phone you never have to think about.
Still unsure? Our is iPhone Duo worth it piece goes through the decision in more depth.
Recording on iPhone Duo? Try PromptSlate Studio
If you pick the Duo because you make videos, PromptSlate Studio is built to use exactly what the Pro Max cannot do: stand the phone in tabletop, keep your script beside the preview, and record without a tripod. See PromptSlate Studio for iPhone Duo.
Related iPhone Duo guides
From the maker
Get PromptSlate Studio on the App Store
Write, prompt and record in one focused workspace. Out now — $9.99 one-time, no subscription. Every download supports independent development of new apps.
See PromptSlate Studio details · Also in the works: DuoSketch
Spotted something to fix, or an app we should cover?
This article is independent research, cross-checked against Apple's developer documentation. If something's out of date, or you know an app that deserves a look, let us know — and if you're building for iPhone Duo yourself, we're happy to talk.
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