iPhone 18 Pro’s aluminum unibody frame is not a new decision. It is the second metal Apple’s Pro iPhone line has landed on since 2021, after a run in stainless steel and a run in titanium. Apple’s own tech specs pages, read side by side, show exactly when each switch happened and how long each material lasted before the next one arrived, without needing to guess at any figure Apple has not itself published.
Lined up by year, the record is not a series of yearly changes. It is two switches, six years apart, with each metal holding for at least two generations before the next one took over.
Key facts
| Model | Year | Frame material (Apple’s tech specs) | Weight |
|---|---|---|---|
| iPhone 13 Pro | 2021 | Stainless steel | 204 g |
| iPhone 14 Pro | 2022 | Stainless steel | 206 g |
| iPhone 15 Pro | 2023 | Titanium | 187 g |
| iPhone 16 Pro | 2024 | Titanium | 199 g |
| iPhone 17 Pro | 2025 | Aluminum unibody | 206 g |
| iPhone 18 Pro | 2026 | Aluminum unibody | 211 g |
Two switches in six years, not six changes
Stainless steel covered iPhone 13 Pro and 14 Pro. Titanium took over for iPhone 15 Pro and 16 Pro, and Apple’s specs page for the 2023 model shows the immediate effect: weight dropped from 206 g to 187 g the year the metal changed, even though the phone’s screen size did not change. Aluminum arrived with iPhone 17 Pro in 2025 and iPhone 18 Pro simply continues it into a second year, at 211 g, the heaviest figure Apple has published for this model across all six years on record.
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Price moved on a similar schedule. iPhone 13 Pro, 14 Pro, 15 Pro and 16 Pro all launched at $999, spanning both the steel and titanium eras. The aluminum era has come with two separate increases: iPhone 17 Pro launched at $1,099 in 2025 and iPhone 18 Pro launched at $1,199 in 2026, both figures from Apple’s own launch pricing.
The Pro Max line shows the same pattern
| Model | Year | Frame material | Weight |
|---|---|---|---|
| iPhone 13 Pro Max | 2021 | Stainless steel | 240 g |
| iPhone 15 Pro Max | 2023 | Titanium | 221 g |
| iPhone 17 Pro Max | 2025 | Aluminum unibody | 233 g |
| iPhone 18 Pro Max | 2026 | Aluminum unibody | 249 g |
The larger model tells the same story on a different scale. Titanium’s arrival in 2023 cut Pro Max weight from 240 g to 221 g, and the aluminum era has climbed back up since, reaching 249 g this year, again the heaviest figure on file for that model.
What stayed constant while the metal changed
One material has not moved at all in that time: the front glass. Apple’s tech specs describe a Ceramic Shield front on iPhone 13 Pro through 16 Pro, and a named upgrade, Ceramic Shield 2, on the front of iPhone 17 Pro and iPhone 18 Pro, with Ceramic Shield also on the back of both aluminum-era phones. Whichever metal wrapped the frame in a given year, the glass on top of it has carried the Ceramic Shield name every single time.
Screen size held steady across a material switch, too. Apple’s tech specs list iPhone 16 Pro’s display, the last titanium-era model, at 6.3 inches, and both iPhone 17 Pro and iPhone 18 Pro carry the same 6.3-inch figure into the aluminum era. The number that moved when titanium arrived, up from iPhone 14 Pro’s 6.1 inches, has not moved again through two full metal changes since.
What Apple has not said
Apple has not published a stated reason for either switch, has not compared stainless steel, titanium and aluminum for scratch or dent resistance on the same page, and has not said whether iPhone 19 Pro keeps aluminum for a third straight year. iPhone 18 Pro pre-orders opened Saturday, September 12, 2026, with the aluminum unibody frame confirmed on Apple’s tech specs page, and the phone reaches stores Friday, September 18. Anyone tracking the next switch will be reading the same kind of tech specs page this article draws on, not a rumor roundup.
