Only 5g Heavier: iPhone Duo vs iPhone 18 Pro Max on Size, Weight, Screen, Crease and Battery
The iPhone Duo weighs 254g, only 5g more than the iPhone 18 Pro Max, and it takes up almost exactly the same space in a pocket. The shape is what changes: folded, it is 45.6mm shorter and 6.1mm wider, but 11.3mm thick against 8.75mm. Open, its 7.6-inch screen has about 50% more area than the Pro Max, yet a widescreen film comes out the same size on both. The Duo costs £700 more at every storage size, and you give up the 4x telephoto camera, Face ID, the Action button and 5 hours of Apple’s UK battery estimate. Buy the Duo if you read, work or browse on your phone for long stretches. Buy the Pro Max if battery life, zoom photos or value matter more.
Jump to your question:
- Is it a brick?254g against 249g, but 2.55mm thicker. Weight and thickness
- Will it fit my pocket?Folded, it is shorter than an iPhone 18 Pro. True-scale drawing
- Is the screen really bigger?For video, pages and photos, yes. For films, no. Screen sizes
- Can you see the crease?At some angles, according to hands-on reports. The crease
- Which lasts longer?The Pro Max, by Apple’s own UK figures. Battery
- Is it worth £700 more?Only if you will use the big screen every day. Who should buy which
- iPhone Duo vs iPhone 18 Pro Max: the specs side by side
- iPhone Duo size and dimensions, folded and open, at true scale
- iPhone Duo weight and thickness: 5g heavier, 2.55mm thicker
- iPhone Duo screen size: bigger open, smaller closed, and the film problem
- The iPhone Duo crease: what hands-on reports saw
- iPhone Duo durability, screen protectors and repair costs
- iPhone Duo battery life vs the Pro Max: 4,883mAh and the UK figures
- iPhone Duo camera vs iPhone 18 Pro Max: no telephoto, no ProRes
- iPhone Duo Face ID? No: Touch ID, no Action button and eSIM only
- Is the iPhone Duo worth it over the iPhone 18 Pro Max?
- Quick answers
iPhone Duo vs iPhone 18 Pro Max: the specs side by side
Both phones run the same A20 Pro chip. Both have 120Hz ProMotion screens that reach 3,000 nits outdoors, MagSafe and Qi2 charging at up to 25W, Wi-Fi 7 and USB-C at USB 3 speeds. So the choice is not about speed. It is about shape, cameras, battery and how you unlock the phone.
| iPhone Duo | iPhone 18 Pro Max | |
|---|---|---|
| Apple UK price, 256GB | £1,999 | £1,299 |
| Apple UK price, 1TB | £2,599 | £1,899 |
| Size, folded (H × W × D) | 117.8 × 84.1 × 11.3mm | 163.4 × 78.0 × 8.75mm |
| Size, open | 117.8 × 164.6 × 5.2mm | Does not fold |
| Weight | 254g | 249g |
| Screens | 7.6in inside, 5.4in outside | 6.9in |
| Typical use (Apple UK) | Up to 24 hours | Up to 29 hours |
| Battery (EU label) | 4,883mAh | 5,391mAh |
| Rear cameras | 48MP main, 48MP ultra wide | Adds a 48MP 4x telephoto |
| Zoom | 2x optical quality | 8x optical quality |
| Unlock | Touch ID in side button | Face ID |
| Action button | No | Yes |
| SIM (UK) | eSIM only | Nano-SIM and eSIM |
| Frame | Grade 5 titanium | Aluminium |
| Colours | Night Sky, Star White | Black, Silver, Glacier, Burgundy |
The price gap is exactly £700 at every storage size, from 256GB to 2TB, at Apple’s UK prices on 19 October. For the release date and where to order, see our iPhone Duo release date and UK price guide.
iPhone Duo size and dimensions, folded and open, at true scale
Folded, the iPhone Duo is 117.8mm tall, 84.1mm wide and 11.3mm thick. The iPhone 18 Pro Max is 163.4mm tall, 78.0mm wide and 8.75mm thick. So the Duo is 45.6mm shorter, about two finger-widths, and 6.1mm wider.
It is even shorter than the smaller iPhone 18 Pro, which is 150.0mm tall. If tall phones poke out of your jeans or dig into you when you sit down, the folded Duo solves that. If you use your phone one-handed with small hands, the extra width is the part to try in a shop first.
Open, the Duo measures 164.6mm across and 117.8mm tall. That is 1.2mm wider than a Pro Max is tall. Picture a Pro Max turned on its side, then add 40mm of height, and you have the open Duo.
Here is the surprising part. As a simple box, ignoring the rounded edges and the camera bump, the folded Duo takes up about 112 cubic centimetres and the Pro Max about 111.5. The two phones fill the same space in your pocket. The Duo just packs it into a shorter, thicker block. The iPhone 18 Pro, for comparison, is about 94.
People weighing up the Duo have noticed the same thing. In a size comparison posted to the r/iPhoneDuo forum on 12 October, the author set the Duo against the 18 Pro rather than the Pro Max because “the folded Duo is pretty small, so more like non-max-territory.” One reply sums up the other side: “folded it’s shorter, yeah. But it’s thicker.” Both are right, and which one matters depends on your pockets.
iPhone Duo weight and thickness: 5g heavier, 2.55mm thicker
How heavy is the iPhone Duo? It weighs 254g, open or closed. The iPhone 18 Pro Max weighs 249g and the iPhone 18 Pro 211g. So in your hand, the Duo feels like a Pro Max, not like two phones stacked together. If you already carry a Pro Max, the weight will not surprise you. If you carry an 18 Pro, it is 43g more.
Thickness is the real trade. Folded, the Duo is 11.3mm thick, against 8.75mm for both 18 Pro models. That is 29% thicker. A case widens the gap: Engadget lists a thin aramid-fibre case that adds 1.7mm, which takes the folded Duo to about 13mm.
Open, it is the thinnest iPhone Apple has made, at 5.2mm. That is thinner than the iPhone Air at 5.64mm, though the Air weighs only 165g. If thin and light is what you are really after, the Air is the phone that delivers both.
Apple iPhone Air 256GB Space Black
Out of stock
£906.95- Super Retina XDR OLED display with 2736 x 1260 resolution, 120 Hz refresh rate, and Ceramic Shield 2 glass
- Powered by the Apple A19 Pro 6-core processor with 16 NPU cores for advanced AI capabilities
- Dual SIM 5G connectivity and Wi-Fi 7 (802.11be) for ultra-fast networking
- Advanced camera system: 48 MP rear with OIS and 18 MP front camera, both supporting HDR
- Durable design with IP68 rating for dust, splash, and water resistance up to 6m
- Equipped with iOS 26, Face Recognition, and an Action Button with customisable features
- Sleek and thin Space Black titanium and ceramic housing, weighing just 165g
iPhone Duo screen size: bigger open, smaller closed, and the film problem
The inner screen is 7.6 inches, with 2670 by 1878 pixels. Apple says it has 50% more area than the 6.9-inch Pro Max, and the pixel counts agree. The outer screen is 5.4 inches. That is about 90% of the screen area of the 6.3-inch iPhone 18 Pro, and about a quarter less than the Pro Max.
The catch is shape. The inner screen is almost square, about 1.42 to 1. The Pro Max screen is long and narrow, about 2.17 to 1. So how much bigger the Duo feels depends on the shape of what you are looking at.
- Widescreen films at 2.39:1 come out the same size on the open Duo as on the Pro Max: 6.21 inches wide against 6.24. Both screens run out of width first, so the Duo just adds black bars above and below.
- YouTube and TV at 16:9 are 48% bigger on the open Duo. So are vertical clips like TikTok or Reels, held upright with the phone open.
- Photos, web pages, e-books and iPad-style apps are more than twice the size: 132% bigger.
- On the outer screen, the Duo loses to the Pro Max for video. A 16:9 or vertical clip is 25% smaller. Only 4:3 content is a little bigger, by 12%.
That is exactly what the r/iPhoneDuo forum argued about in a thread on 5 October. Its starter worried that “you get about the same size screen for movies, the Duo just has letterboxing.” The replies that held up were not about films. They were about documents, note taking, spreadsheets and reading. If those are what you do on your phone, the Duo is a genuine upgrade. If you mostly watch films, it is not.
Both Duo screens share the same shape, so an app does not jump around when you open the phone. The inner screen is slightly less sharp, at 430 pixels per inch against 460 on the Pro Max, which you are unlikely to notice at arm’s length. It also has a matte nano-texture finish that cuts reflections.
The Duo’s inner screen also works with the Apple Pencil (USB-C), which Apple says is coming later this year. No iPhone 18 Pro model supports a Pencil. If you sketch or write notes by hand, that is a real reason to pick the Duo.
Apple Pencil (USB-C)
In stock
Original price was: £100.79.£94.78Current price is: £94.78.Apple Pencil (USB-C). Supports tilt sensitivity and magnetic attachment for storage. Pairing and charging use a USB-C cable. Requires iPadOS 17.1.1 or later.
The iPhone Duo crease: what hands-on reports saw
Every folding screen has a crease where it bends. Apple’s answer is a matte inner screen and layers that slide over each other as it folds, which Apple says minimises stress and creasing. Apple does not claim the crease is gone.
Hands-on reports from Apple’s September launch agree that it is hard to see but not invisible:
- MacRumors said the crease is “visible in certain lighting”, but that Apple did a better job than Samsung at hiding it.
- Gizmodo could still see it “at various angles”, but could not feel it under a finger, unlike on other foldables.
- Heise found that the matte surface “cleverly conceals the crease”.
The bigger question is whether it gets worse. On older foldables, a faint crease often became more obvious after months of use. Apple’s Tom Marieb told Trusted Reviews: “Hold us accountable to that, please.” He said the matte finish is more forgiving of “any of those changes over time”. Nobody outside Apple has had a Duo long enough to test that yet. Full reviews with longer use are expected around the 23 October launch.
The iPhone 18 Pro Max has no crease, because its screen does not fold. If you are open to a foldable but not set on Apple, Samsung’s Galaxy Z Fold8 has the same book-style design, and our Galaxy Z Fold8 vs Fold8 Ultra comparison covers it.
Samsung Galaxy Z Fold8 Enterprise Edition Smartphone, 19.3 cm (7.6″) Dynamic AMOLED 2X Display, 12 GB RAM, 256 GB Storage, 5G
In stock
£1,870.87- Display featuring a 19.3 cm (7.6″) Dynamic AMOLED 2X main screen with 1848 x 2448 pixels and a 14 cm (5.5″) secondary display
- Processor powered by 8 cores with a 4.74 GHz boost frequency, 12 GB RAM, and 256 GB internal storage
- Camera system equipped with multiple 50 MP rear lenses and 10 MP front and cover cameras supporting Optical Image Stabilisation
- Connectivity supporting 5G mobile networks, Dual SIM, Wi-Fi 7, Bluetooth, and NFC capabilities
- Battery capacity of 4800 mAh providing up to 26 hours of wireless video playback through a USB Type-C charging port
- Form factor designed in a clamshell folding style with a weight of 201 g
iPhone Duo durability, screen protectors and repair costs
The Duo’s frame and hinge cover are grade 5 titanium. The outer screen and back use Ceramic Shield, and the phone is rated IP68 for water and dust, the same as the Pro Max. Apple has not published how many folds the hinge is rated for, so long-term durability is something only time and independent testing will show.
The weak point is the inner screen. Its top layer is a polymer film rather than glass. Apple will replace that layer if it wears or scratches, for $49 in the US, or $19 with AppleCare+.
Screen protectors: never put a tempered glass protector on the inner screen. Engadget warns it will crack when you close the phone. If you want one, use a flexible TPU or PET film made for the Duo.
Repairs cost far more than on a Pro Max if you break the phone without AppleCare+. Apple’s US estimates are:
- Inner screen: $999, against $379 for a Pro Max screen.
- “Other damage”: $1,499, against $899.
- Battery: $229, against $129.
With AppleCare+, the inner screen fee drops to $99. Apple’s German prices tell the same story, with €1,149 for the inner screen. Check Apple’s UK repair pages for the sterling figures before you decide on cover. On a Duo, AppleCare+ is easier to justify than on any other iPhone.
On the EU’s new phone label, the Duo scores a C for repairability, 2.65 out of 5, the same class as the 18 Pro models. Its battery is rated to keep its performance for at least 1,000 charge cycles.
iPhone Duo battery life vs the Pro Max: 4,883mAh and the UK figures
Apple’s EU energy label, published on 16 October, puts the Duo’s battery at 4,883mAh, split across two cells, one in each half. The Pro Max sold in the UK and EU keeps a SIM tray, and its own label rates its battery at 5,391mAh. That is about 10% more, with only one screen to power at a time.
Apple’s UK battery estimates for typical use are:
- iPhone Duo: up to 24 hours.
- iPhone 18 Pro Max: up to 29 hours.
- iPhone 18 Pro: up to 23 hours.
Many US sites quote 30 hours for the Pro Max. That is Apple’s US figure for the American model, which has no SIM tray and a larger battery. In the UK, the gap to the Duo is 5 hours.
How you use the Duo matters more than on a normal phone. Apple rates video playback at up to 44 hours on the outer screen, but only 31 hours on the inner screen. A UK Pro Max manages 43 hours. If you plan to keep the Duo open most of the day, expect noticeably less than from a Pro Max.
Charging is a little slower too. With a 60W-capable charger, the Duo reaches 50% in about 20 minutes, against about 15 minutes for the Pro Max. Most MagSafe battery packs will charge it, but they overhang its shorter body. If you rely on one, our best power bank guide covers the MagSafe options.
iPhone Duo camera vs iPhone 18 Pro Max: no telephoto, no ProRes
This is the widest gap between the two phones. The Duo has two rear cameras: a 48MP main camera and a 48MP ultra wide. The Pro Max adds a 48MP telephoto with 4x zoom. That gives it 8x optical-quality zoom against the Duo’s 2x, and digital zoom to 40x against 10x.
The Pro Max’s main camera also has a variable aperture, from f/1.48 to f/4.0, plus Pro controls for shutter speed and aperture. It shoots ProRAW photos and records ProRes, ProRes RAW and Apple Log video, and it has a LiDAR scanner. The Duo saves photos as HEIF or JPEG and video as HEVC or H.264.
The Duo does have tricks of its own. With Duo Preview, the person you are photographing sees the shot on the outer screen. Smart Take waits until everyone is in the frame before it takes a group photo. And you can stand the phone half-folded for time-lapses without a tripod.
For everyday photos, both main cameras are 48MP. But if you shoot your children at sports day, wildlife, gigs or anything far away, the Pro Max is the better camera by a distance. To see what changed from last year’s Pro camera, read our iPhone 18 Pro vs iPhone 17 Pro comparison.
iPhone Duo Face ID? No: Touch ID, no Action button and eSIM only
The Duo unlocks with a fingerprint sensor in the side button, so it works the same way open or closed. There is no Face ID. If you have used Face ID for years, expect a few weeks of reaching for the button. Gizmodo called the loss “a step backward”, though not a dealbreaker.
The Action button is gone too. You keep Camera Control and the volume buttons, but there is no customisable button and no physical way to silence the phone.
The Duo uses eSIM only. UK versions of the 18 Pro models still have a nano-SIM slot as well. If you move a physical SIM between phones, or buy local SIM cards when you travel, the Pro Max is easier.
Two smaller losses: Apple lists MagSafe cases and chargers for the Duo, but not MagSafe wallets. And Apple’s own silicone case for the Duo sticks on with adhesive rather than clipping on, so swapping cases or going without one is less easy than on a Pro Max.
Is the iPhone Duo worth it over the iPhone 18 Pro Max?
Start with the money. The Duo costs £700 more at every storage size: £1,999 against £1,299 for 256GB, and £3,199 against £2,499 for 2TB. Repairs and AppleCare+ cost more as well.
Buy the iPhone Duo if:
- You read, edit documents, use spreadsheets or browse for long stretches on your phone.
- You carry a small tablet as well as a phone, and want to carry one device.
- You want a big screen but hate how long the Pro Max is in a pocket.
- You want to write or sketch with an Apple Pencil once support arrives.
Buy the iPhone 18 Pro Max if:
- Battery life matters most to you.
- You use zoom, or you shoot video seriously.
- You like Face ID, the Action button or a physical SIM.
- You mostly watch films, which are no bigger on the Duo.
- You want the best value, or you are wary of a first-generation folding screen.
What we would actually do: wait for the first full reviews before paying £1,999. On the day pre-orders opened, 16 October, new orders on Apple’s US store were already quoting delivery in late January. If you have not ordered yet, a few weeks spent reading crease and battery tests costs you very little.
Quick answers
Open, yes: its 7.6-inch screen has about 50% more area than the Pro Max’s 6.9-inch screen. Folded, no: it is 117.8mm tall against 163.4mm, though it is wider (84.1mm against 78.0mm) and thicker (11.3mm against 8.75mm).
Folded, it is 117.8mm tall, 84.1mm wide and 11.3mm thick. Open, it is 117.8mm tall, 164.6mm wide and 5.2mm thick. It weighs 254g either way.
It is 163.4mm tall, 78.0mm wide and 8.75mm thick, weighs 249g and has a 6.9-inch screen.
By 2026 standards, yes. The iPhone 18 Pro is 6.3 inches and the Pro Max 6.9. But the Duo’s outer screen is wider and shorter than a normal iPhone screen, so it still has about 90% of the iPhone 18 Pro’s screen area.
Open, yes: 5.2mm against 5.64mm, which makes it the thinnest iPhone so far. Folded, it is 11.3mm, twice as thick as the Air, and at 254g it is 89g heavier.
No. It uses Touch ID, a fingerprint sensor built into the side button, which works whether the phone is open or closed.
Yes, but it is hard to see. Hands-on reports say it shows at some angles and in certain lighting, and cannot be felt under a finger. Apple says its matte inner screen will hide changes over time; full reviews are expected around the 23 October launch.
Not a glass one on the inner screen, which would crack when you close the phone. Use a flexible TPU or PET film made for the Duo. The inner screen’s top layer is also replaceable by Apple ($49 in the US, $19 with AppleCare+).
Than the iPhone Duo, yes, for zoom and serious video. The Pro Max has a 4x telephoto, 8x optical-quality zoom, ProRAW, ProRes and Apple Log. The Duo has a 48MP main and a 48MP ultra wide camera with 2x optical-quality zoom.
The Pro Max. Apple’s UK figures give it up to 29 hours of typical use against 24 for the Duo, and its battery is rated at 5,391mAh against 4,883mAh.
Pre-orders opened on 16 October, and the iPhone Duo goes on sale on 23 October, from £1,999 in the UK. New orders on Apple’s US store were soon quoting late January delivery.
Sources
- Apple UK: iPhone Duo technical specifications: dimensions, weight, screens, cameras, battery, Touch ID, eSIM, colours and Apple Pencil (USB-C) support.
- Apple UK: iPhone 18 Pro technical specifications: Pro and Pro Max dimensions, weight, cameras, UK battery estimates, Action button and nano-SIM.
- Apple US: iPhone 18 Pro technical specifications: the US battery estimates (30 hours for the eSIM-only Pro Max).
- Apple UK: iPhone Duo: the 50% and 90% screen area claims, materials, durability and Apple’s answer on the crease.
- Apple UK Store: iPhone Duo and iPhone 18 Pro: UK prices at each storage size, 19 October 2026.
- Apple UK: iPhone Air technical specifications: thickness and weight.
- MacRumors: iPhone Duo hands-on: the crease in certain lighting, cameras and price.
- Gizmodo: iPhone Duo hands-on: the crease at various angles and the loss of Face ID.
- Heise: iPhone Duo hands-on: the matte surface and the crease.
- Trusted Reviews: interview with Apple’s Tom Marieb: how the crease should age.
- The Mac Observer: the hinge and display interview: no published fold-count rating.
- MacRumors: iPhone Duo compromises: US repair estimates, AppleCare+, the cover layer, the Action button, eSIM and MagSafe wallets.
- The Verge: iPhone Duo repair costs: the $999 inner screen and $99 AppleCare+ fee.
- Yahoo News UK (TECHBOOK): iPhone Duo repair costs: Apple’s German repair prices.
- MacRumors: iPhone Duo battery capacity: the 4,883mAh EU label and its two cells.
- GSMArena: iPhone 18 Pro and Pro Max EU labels: the 5,391mAh rating, the SIM-tray models and the C repairability class.
- iThinkDifferent: iPhone Duo EU label: the C repairability score of 2.65 and 1,000 charge cycles.
- Engadget: which accessories fit the iPhone Duo: case thickness, glass protectors and MagSafe battery packs.
- r/iPhoneDuo: Duo beside the 18 Pro Max (5 October) and Duo vs 18 Pro size comparison (12 October): what buyers are weighing up.
- 9to5Mac: Apple’s silicone Duo case needs adhesive.
- PCMag UK: Duo delivery dates stretch into 2027: the late January delivery quote.
- Photos: iPhone 18 Pro and Pro Max and Back Camera of iPhone 18 Pro Max by Kyu3a, on Wikimedia Commons under CC BY-SA 4.0, cropped. iPhone Duo product images from the Apple Newsroom.
