Apple’s iPhone Duo starts at $1,999, while iPhone 18 Pro starts at $1,199, according to Apple’s online store. Apple opened Duo pre-orders on October 16 and says the foldable will be available starting on October 23, 2026.
Both phones use the same A20 Pro chip, but Apple’s spec sheets show the Duo gives up several iPhone 18 Pro hardware features in exchange for its foldable titanium design. Here is how the two compare, using only the numbers Apple publishes. For performance testing, see our iPhone Duo benchmark comparison.
Size and weight
| Spec | iPhone Duo (open) | iPhone Duo (closed) | iPhone 18 Pro | iPhone 18 Pro Max |
|---|---|---|---|---|
| Width | 164.6 mm | 84.1 mm | 71.9 mm | 78.0 mm |
| Height | 117.8 mm | 117.8 mm | 150.0 mm | 163.4 mm |
| Depth | 5.2 mm | 11.3 mm | 8.75 mm | 8.75 mm |
| Weight | 254 grams | 254 grams | 211 grams | 249 grams |
| Design | Titanium foldable | Titanium foldable | Aluminum unibody | Aluminum unibody |
The Duo weighs 254 grams open or closed, which makes it heavier than both iPhone 18 Pro at 211 grams and iPhone 18 Pro Max at 249 grams.
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Thickness depends on how you hold it. Opened, Apple says the Duo is the thinnest iPhone ever at 5.2 mm. Folded, it measures 11.3 mm, thicker than the 8.75 mm of both 18 Pro models. Closed, it is also much shorter than an 18 Pro, at 117.8 mm tall against 150.0 mm.
Displays
| Display | iPhone Duo | iPhone 18 Pro | iPhone 18 Pro Max |
|---|---|---|---|
| Main screen | 7.6-inch inner folding OLED, 1878-by-2670 at 430 ppi | 6.3-inch OLED, 2622-by-1206 at 460 ppi | 6.9-inch OLED, 2868-by-1320 at 460 ppi |
| Second screen | 5.4-inch outer OLED, 1398-by-2034 at 460 ppi | None | None |
| Refresh rate | ProMotion up to 120Hz | ProMotion up to 120Hz | ProMotion up to 120Hz |
| Brightness | 1000 nits typical, 1600 nits HDR, 3000 nits outdoor | Same | Same |
Apple says the Duo’s inner display is 50 percent larger than the display on iPhone 18 Pro Max, and that the outer display delivers 90 percent of the screen area of iPhone 18 Pro.
Both Duo displays get Dynamic Island, Always-On and the same 1 nit minimum brightness as the 18 Pro. The inner display adds a nano-texture finish, which does not appear on the iPhone 18 Pro spec sheet.
Cameras
This is where the gap is widest. The Duo has two rear cameras, and the 18 Pro models have three.
| Camera | iPhone Duo | iPhone 18 Pro and Pro Max |
|---|---|---|
| Rear system | 48MP Dual Fusion | 48MP Pro Fusion |
| Main | 48MP, 26 mm, ƒ/1.6 | 48MP, 24 mm, variable aperture (ƒ/1.48, ƒ/1.8, ƒ/2.8, ƒ/4.0) |
| Ultra Wide | 48MP, 13 mm, ƒ/2.2 | 48MP, 13 mm, ƒ/2.2 |
| Telephoto | 12MP optical-quality 2x (52 mm), from the Main camera | 48MP Fusion Telephoto, 100 mm (4x), ƒ/2.8, plus 12MP optical-quality 8x (200 mm) |
| Optical-quality zoom range | 4x | 16x |
| Digital zoom (photos) | Up to 10x | Up to 40x |
| Front | 12MP Center Stage, ƒ/2.2 (outer), plus under-display FaceTime camera, ƒ/1.8 (inner) | 18MP Center Stage, ƒ/1.9 |
| Photo formats | HEIF and JPEG | HEIF, JPEG, and DNG |
| Video formats | HEVC and H.264 | HEVC, H.264, ProRes, and ProRes RAW |
Apple’s store comparison lists optical zoom options of .5x, 1x and 2x for the Duo and marks it as lacking the 18 Pro’s variable aperture, Pro controls and Apple Reference Image. On the 18 Pro, Pro controls cover lens aperture, shutter speed, white balance and a histogram.
The Duo does get two camera features the 18 Pro lacks in that comparison: Smart Take and Duo Preview. Both phones record 4K Dolby Vision video at up to 120 fps on the Fusion Main camera.
Buttons, unlocking and sensors
The Duo has volume buttons, Camera Control and a side button with a built-in Touch ID fingerprint sensor. Apple’s store comparison lists it with no Action button. iPhone 18 Pro keeps the Action button alongside Camera Control and uses Face ID, enabled by TrueDepth technology in the front camera.
The iPhone 18 Pro sensor list also includes a LiDAR Scanner, which is not on the Duo’s list.
What the two share
- A20 Pro chip with a 6-core CPU, 7-core GPU with Neural Accelerators and Dual 16-core Neural Engine
- Storage options of 256GB, 512GB, 1TB and 2TB
- IP68 rating, up to 6 meters for up to 30 minutes
- Apple N1 chip with Wi-Fi 7 and Bluetooth 6, and the Apple C2 cellular modem on iPhone 18 Pro and Duo
- MagSafe and Qi2 wireless charging up to 25W, and USB-C with USB 3 speeds up to 10Gb/s
- Dual eSIM, with no physical SIM support in the U.S. models
Battery life is the one area where the answer depends on how you use the Duo. Apple rates it for up to 44 hours of video playback on the outer display and up to 31 hours on the inner display, against up to 36 hours for iPhone 18 Pro.
Price and colors
iPhone Duo starts at $1,999 for 256GB and comes in Night Sky and Star White. iPhone 18 Pro starts at $1,199 and comes in Black, Silver, Glacier and Burgundy. Apple’s iPhone Duo pre-order announcement covers trade-in, Apple Upgrade and carrier offers, and we covered the pre-order launch when it opened.
