The iPhone 18 Pro Max is Apple’s biggest current iPhone, and its size is the first thing most buyers ask about before ordering one. It has a 6.9-inch display, but the screen size alone does not tell you how the phone feels in your hand or whether it fits comfortably in your pocket. In this guide, you will find the iPhone 18 Pro Max dimensions in inches, centimetres and millimetres, its exact weight, and simple comparisons with the smaller iPhone 18 Pro and last year’s iPhone 17 Pro Max — so you can picture its real size before you buy it.
iPhone 18 Pro Max Dimensions at a Glance
| Measurement | Inches | cm | mm |
|---|---|---|---|
| Height | 6.43 in | 16.34 cm | 163.4 mm |
| Width | 3.07 in | 7.80 cm | 78.0 mm |
| Thickness | 0.34 in | 0.88 cm | 8.75 mm |
| Display diagonal | 6.9 in | 17.53 cm | 175.3 mm |
| Weight | 8.78 oz | 249 g | – |
Quick tip: The 6.9-inch figure is the screen diagonal, measured corner to corner. The phone body itself is 6.43 inches tall and 3.07 inches wide.
How Tall Is the iPhone 18 Pro Max?
At 6.43 inches (16.34 cm) tall, the iPhone 18 Pro Max is about as tall as a standard ballpoint pen, and slightly taller than a credit card turned on its long side twice over. For most people, this is a two-hand phone for typing long messages, though one-handed use is possible if you have larger hands.
How Wide Is the iPhone 18 Pro Max?
The phone is 3.07 inches (7.80 cm) wide. That width is what decides whether it feels comfortable in one hand. It is noticeably wider than the smaller iPhone 18 Pro, which is 2.83 inches wide — a difference of 0.24 inches (6.1 mm) that you can feel the moment you hold both phones side by side.
How Thick Is the iPhone 18 Pro Max?
At 0.34 inches (8.75 mm) thick, the iPhone 18 Pro Max is about one-third of an inch thick — roughly the thickness of three stacked credit cards. The raised camera area on the back adds a little more.
How Much Does the iPhone 18 Pro Max Weigh?
The iPhone 18 Pro Max weighs 249 grams (8.78 ounces), just over half a pound. That makes it the heaviest non-folding iPhone Apple has made so far, and 16 grams heavier than the iPhone 17 Pro Max. For comparison, 249 grams is about the weight of a small paperback book, or a can of soup.
iPhone 18 Pro Max vs iPhone 18 Pro: Size Comparison
| Feature | iPhone 18 Pro Max | iPhone 18 Pro | Difference |
|---|---|---|---|
| Display | 6.9 in | 6.3 in | 0.6 in larger |
| Height | 6.43 in (163.4 mm) | 5.91 in (150.0 mm) | 0.52 in taller |
| Width | 3.07 in (78.0 mm) | 2.83 in (71.9 mm) | 0.24 in wider |
| Thickness | 0.34 in | 0.34 in | same |
| Weight | 8.78 oz (249 g) | 7.44 oz (211 g) | 1.34 oz heavier |
Both phones are exactly the same thickness, so the choice comes down to height, width and weight — not thickness.
iPhone 18 Pro Max vs iPhone 17 Pro Max
The iPhone 18 Pro Max has exactly the same height, width and thickness as the iPhone 17 Pro Max: 163.4 x 78.0 x 8.75 mm. The only published dimension that changed is weight — 249 grams against 233 grams last year, a 16-gram increase. Apple has not guaranteed case interchangeability, because button positions and the camera area can differ slightly.
Does the iPhone 18 Pro Max Fit in Your Pocket?
Yes, for most regular trouser and jacket pockets. At 6.43 inches tall and 3.07 inches wide, it slides into a standard pocket, though it will fill it more completely than a smaller phone. In tight jeans pockets it may feel snug when you sit down, so a jacket pocket or bag is more comfortable for all-day carrying.
Everyday Size Comparisons
- Taller than a dollar bill (a US dollar bill is 6.14 inches long; the phone is 6.43 inches tall).
- Wider than a credit card (a credit card is 2.13 inches wide; the phone is 3.07 inches wide).
- About half a pound (at 8.78 ounces, just over half a pound, similar to a small paperback).
- Thinner than a pencil is long — at 0.34 inches thick, it is far thinner than it is tall or wide.
Frequently Asked Questions
How many inches is the iPhone 18 Pro Max?
It is 6.43 inches tall, 3.07 inches wide and 0.34 inches thick. Its display measures 6.9 inches diagonally.
How much does the iPhone 18 Pro Max weigh in grams?
It weighs 249 grams, which is 8.78 ounces — 16 grams more than the iPhone 17 Pro Max.
Is the iPhone 18 Pro Max bigger than the iPhone 18 Pro?
Yes. It is 0.52 inches taller, 0.24 inches wider and 1.34 ounces heavier. Both are the same 0.34 inches thick.
Will an iPhone 17 Pro Max case fit the iPhone 18 Pro Max?
The two phones share the same listed outer dimensions, so some cases may appear to fit, but Apple has not guaranteed interchangeability. Check the case maker’s compatibility list first.
Is the iPhone 18 Pro Max too big for one hand?
It depends on your hand size. Most people find it comfortable for watching videos and reading, but typing long messages is easier with two hands.
Conclusion
The iPhone 18 Pro Max measures 6.43 x 3.07 x 0.34 inches (163.4 x 78.0 x 8.75 mm) and weighs 249 grams, with a 6.9-inch display. It is the same size as last year’s Pro Max but a little heavier, and it is clearly larger and heavier than the smaller iPhone 18 Pro while sharing the same thickness. If you want the biggest screen and longest battery life, the Pro Max size is worth it. If you want easier one-handed use, the smaller iPhone 18 Pro — at 5.91 inches tall and 211 grams — will feel much more comfortable in your hand.
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Hi, I’m Michael Carter, I write simple, everyday size guides so you can picture any measurement in seconds.