iPhone Duo size and weight compared

The iPhone Duo weighs 254 g and measures 117.8 x 84.1 x 11.3 mm closed, according to Apple's iPhone Duo spec page. That makes it almost exactly as heavy as an iPhone 18 Pro Max, but a very different shape: much shorter, a little wider and noticeably thicker.

Here's how that plays out on paper. The differences below are our own arithmetic from official spec sheets.

The numbers side by side

Apple says size and weight vary by configuration and manufacturing process. The Galaxy Z Fold 8 figures come from Google Fi's Galaxy Z Fold8 spec sheet, with the cover screen size from GSMArena's Galaxy Z Fold 8 review.

Our table, built from Apple's spec pages for the iPhone 18 Pro models, iPhone Air and iPad mini, plus Google Fi and GSMArena. Everything else is in the full iPhone Duo specifications.

In imperial, Apple lists the iPhone Duo at 4.64 x 3.31 x 0.44 inches closed and 8.96 ounces. For Samsung, our conversion: the Galaxy Z Fold 8 works out to about 7.09 oz (201 g divided by 28.35 g per ounce) and 0.38 inch thick closed (9.7 mm divided by 25.4 mm per inch).

Versus iPhone 18 Pro Max: same weight, different shape

The iPhone Duo is 5 g heavier than the iPhone 18 Pro Max (254 g minus 249 g), about 2%. Closed, it is 2.55 mm thicker (11.3 mm minus 8.75 mm) and 6.1 mm wider (84.1 mm minus 78.0 mm).

The big change is height. Closed, the iPhone Duo is 45.6 mm shorter (163.4 mm minus 117.8 mm), so its footprint is about 22% smaller (99.1 square cm vs 127.5 square cm, height times width). Multiply in thickness and the two rectangular boxes are nearly identical: about 111.9 cubic cm for the iPhone Duo and 111.5 cubic cm for the iPhone 18 Pro Max. That rough bounding-box math ignores rounded corners, but the point stands: same bulk, stubbier block.

Unfolded, the iPhone Duo is 164.6 mm wide, which is 1.2 mm more than the iPhone 18 Pro Max is tall. More on that matchup in iPhone Duo vs iPhone 18 Pro Max.

Versus iPhone 18 Pro and iPhone Air: the gap gets real

Against the iPhone 18 Pro, the iPhone Duo is 43 g heavier (254 g minus 211 g) and 2.55 mm thicker closed. Against the iPhone Air, it's 89 g heavier (254 g minus 165 g), or about 54% more, and twice as thick closed (11.3 mm vs 5.64 mm).

Open, though, the iPhone Duo is 5.2 mm thick, which is 0.44 mm thinner than an iPhone Air. Neat trick, but you carry it closed.

Versus Galaxy Z Fold 8: Samsung is lighter and slimmer

Credit where due: the Galaxy Z Fold 8 is the lighter foldable on paper. It weighs 201 g, so the iPhone Duo is 53 g heavier, and Samsung's phone is 1.6 mm thinner closed (11.3 mm minus 9.7 mm) and 0.7 mm thinner open (5.2 mm minus 4.5 mm). Closed, the iPhone Duo is 6.1 mm shorter and 2.2 mm wider. The rest of that comparison lives in iPhone Duo vs Galaxy Z Fold 8.

Versus iPad mini: about the same weight, three-quarters of the area

Apple's new iPad mini (A20 Pro) weighs 255 g in its Wi-Fi version, so the iPhone Duo is 1 g lighter, and 9 g lighter than the 263 g cellular model.

Open, the iPhone Duo covers about 75% of the iPad mini's footprint (193.9 vs 259.0 square cm) with a 7.6-inch screen against 8.5 inches, and it's 0.2 mm thinner. If the iPhone Duo would replace an iPhone 18 Pro plus an iPad mini, that pair weighs 466 g together (211 g plus 255 g). More in iPhone Duo vs iPad mini.

What reviewers said about carrying it

Macworld's review roundup quotes reviewers on both sides of pocketability. 9to5Mac found the iPhone Duo surprisingly comfortable to carry: "Its shorter, wider footprint makes a bigger difference than I expected."

Gizmodo saw the other side: the iPhone Duo made a front trouser pocket sag enough to call for a belt, after the reviewer had grown used to the iPhone Air's lightness.

A case changes the math

Any case adds weight and thickness. As one example, OtterBox lists its Lumen Series case for iPhone Duo at 58.26 g, which would bring the total to about 312 g (254 g plus 58.26 g). Compare options in the best iPhone Duo cases.

Who should care

iPhone 18 Pro Max owners get a wash on weight and a shorter shape that may suit front pockets better, but a thicker brick. If you're coming from an iPhone Air or iPhone 18 Pro, the extra 43 g to 89 g is the number to think about. If the iPhone Duo would let you leave an iPad mini at home, the weight math is the strongest argument for it.

Not sure the size trade-off is worth $1,999 and up in the US (as of Oct 31, 2026)? Start with should you buy an iPhone Duo.