iPhone 18 Pro vs Pro Max vs Duo: Which One Should You Buy?
2026-09-23
2026 iPHONE BUYING GUIDE
iPhone 18 Pro, Pro Max or Duo? Price, screen, camera and battery compared
The 2026 iPhone question is no longer just "big Pro or small Pro". Alongside the iPhone 18 Pro and iPhone 18 Pro Max, Apple has added its first foldable, the iPhone Duo — so the choice shifts from a size difference to a decision between a conventional flagship and a large folding screen.
Rather than reciting three spec sheets, this compares them on price, display, performance, camera, battery life and how you would actually use them.
The short answer
iPhone 18 Pro: full Pro performance and cameras, in a size that is still manageable.
iPhone 18 Pro Max: a conventional iPhone, but with the 6.9-inch screen and the longest battery life.
iPhone Duo: a higher budget, for a 7.6-inch folding display, multitasking and a genuinely different way of using a phone.
Quick compare
Item
iPhone 18 Pro
iPhone 18 Pro Max
iPhone Duo
From
NT$44,900
NT$49,900
NT$74,900
Display
6.3-inch
6.9-inch
7.6-inch inner + 5.4-inch outer
Chip
A20 Pro
A20 Pro
A20 Pro
Cameras
Pro Fusion, three
Pro Fusion, three
Dual Fusion
The point of it
Balanced Pro, easy to hold
Large screen, long battery
Folding screen, dual-screen multitasking
01｜Price
NT$44,900, NT$49,900 and NT$74,900 respectively. The gap between the 18 Pro and the Duo is NT$30,000.
02｜Display and size: 6.3, 6.9 or 7.6 inches?
The Pro and Pro Max differ only in size. The Duo is a different proposition: 7.6 inches when opened, 5.4 inches on the cover screen, so it folds down to something you can use one-handed.
03｜Performance: all three use the A20 Pro
All three carry the same A20 Pro — 6-core CPU, 7-core GPU, two 16-core Neural Engines. The Duo does not get a higher-tier chip for being more expensive.
What differs is the body that performance sits in. The 18 Pro series is built around Pro cameras, gaming and heavy workloads; the Duo uses the 7.6-inch space to extend that performance into multitasking, reading and different fold positions.
04｜Cameras: three Pro lenses vs dual Fusion
If photography comes first, the 18 Pro and Pro Max are the more direct answer: a 48MP Pro Fusion system with main, ultra-wide and telephoto, and 0.5x, 1x, 2x, 4x and 8x optical zoom options.
The Duo uses a 48MP dual Fusion system. Its advantage is not an extra lens but what the fold makes possible — your subject can check their own framing on the outer screen as you shoot.
Simply put: full lens coverage and zoom flexibility → Pro / Pro Max. Folding compositions, dual-side preview and new ways of shooting → Duo.
05｜Battery and charging
Apple rates the iPhone 18 Pro series at up to 43 hours of video playback. The Duo has two figures because it has two screens: up to 44 hours on the outer display, up to 31 hours on the 7.6-inch inner display.
So "44 hours" does not make the Duo automatically longer-lasting than the Pro Max. Real battery life depends on whether you are using the cover screen or the open display, plus brightness, network and app load.
06｜What does the extra NT$30,000 buy?
Comparing base models, the Duo costs NT$30,000 more than the iPhone 18 Pro. That gap does not buy a faster chip. It buys the folding body, the 7.6-inch inner and 5.4-inch outer displays, dual-screen interaction, multitasking and the different placement angles.
Which is why dividing specification by price is the wrong test. If you mostly use a phone as a conventional slab, the 18 Pro series makes more sense. If you will genuinely read, take calls, work or handle two things at once on the open screen, the difference shows up every day.
07｜Who is each one for?
iPhone 18 Pro — the balanced Pro. For anyone who values camera, performance and portability. You want a Pro, but not necessarily a large screen.
iPhone 18 Pro Max — the conventional large flagship. The same Pro capability with the biggest screen and the longest battery, in a familiar shape.
iPhone Duo — the one that changes how you use a phone. Worth it only if you will actually use the open display. Then the NT$30,000 turns into a difference you feel daily.
FAQ
Q1. What is the main difference between the 18 Pro and Pro Max?
Size and price. The 18 Pro is 6.3-inch, the Pro Max 6.9-inch. Both use the A20 Pro and the same Pro Fusion camera system.
Q2. How much more is the iPhone Duo?
At base prices, the Duo is NT$74,900 against NT$44,900 for the 18 Pro — a difference of NT$30,000.
Q3. Do all three use the A20 Pro?
Yes. Which is exactly why the decision should rest on size, camera, the folding design and how you use the phone.
Q4. For photography, Duo or Pro?
For full lens coverage and zoom flexibility, the 18 Pro / Pro Max triple Pro Fusion system. The Duo's strength is the dual-screen shooting the fold makes possible.
Q5. Is the Duo worth NT$30,000 more?
It depends on whether you will regularly use the 7.6-inch open screen, multitasking and folded modes. If you mostly use it as an ordinary phone, the 18 Pro series is the better value.
Picked your iPhone — what about the charging gear?
Charger, cable and power bank, matched to how you actually use the phone.
Compiled from Apple's published 2026 material. Specifications, prices and features follow Apple's latest announcements.
