PCMag measured 34 hours and 31 minutes from the iPhone 18 Pro Max in a maximum-brightness YouTube-over-Wi-Fi test published on September 21, 2026. That was 2 hours and 20 minutes longer than the iPhone 17 Pro Max under the same test. Two days earlier, PhoneArena recorded 61% charge after five hours and 42% after seven hours of controlled YouTube streaming, with the iPhone 18 Pro Max ahead of the other three phones in its comparison.
Two recent tests put the iPhone 18 Pro Max ahead
The September 21 PCMag result is the clearest single runtime figure so far: 34 hours and 31 minutes with the display at maximum brightness, YouTube streaming over Wi-Fi, and the screen kept active. The result placed the iPhone 18 Pro Max 2 hours and 20 minutes ahead of the iPhone 17 Pro Max, which reached 32 hours and 11 minutes in the same test.
PhoneArena used a different approach. Its comparison kept the phones at the same brightness, used the same Wi-Fi network and playlist, and tracked the remaining charge during continuous YouTube playback. The iPhone 18 Pro Max had 61% remaining at the five-hour mark and 42% at seven hours. It finished ahead of the iPhone 17 Pro Max, Samsung Galaxy S26 Ultra, and Google Pixel 11 Pro XL at both checkpoints.
What each test measured
These results answer slightly different questions. PCMag ran the phones until depletion and reported total runtime. PhoneArena reported the percentage remaining at fixed checkpoints during a shared streaming workload. Brightness, network conditions, battery health, software, and the type of work a phone performs can all affect the result.
That is why Apple’s figures belong in a separate category. Apple rates the US eSIM-only iPhone 18 Pro Max for up to 45 hours of video playback and up to 30 hours of typical use. Those are manufacturer ratings based on Apple’s usage models, rather than a replacement for either independent test.
iPhone 18 Pro Max battery comparison
PhoneArena’s four-phone streaming comparison produced these remaining-charge figures:
| Model | Battery remaining after 5 hours of YouTube | Battery remaining after 7 hours of YouTube | Battery capacity in the test |
| iPhone 18 Pro Max | 61% | 42% | 5,391mAh |
| iPhone 17 Pro Max | 48% | 22% | 4,823mAh |
| Samsung Galaxy S26 Ultra | 50% | 27% | 5,000mAh |
| Google Pixel 11 Pro XL | 57% | 37% | 5,115mAh |
The table shows the iPhone 18 Pro Max retaining the highest charge at both checkpoints. It does not turn the seven-hour streaming result into a prediction for mixed everyday use; it is a comparison under PhoneArena’s stated workload.
Why the reported capacity varies by model
The iPhone 18 Pro Max does not have one reported capacity figure across the tested configurations. PCMag’s US eSIM-only model was reported at 5,567mAh. PhoneArena used a physical-SIM/global version reported at 5,391mAh.
Those figures belong to different hardware configurations. The 5,567mAh capacity should not be transferred to the physical-SIM/global model, and the 5,391mAh figure should not be presented as the capacity of the US eSIM-only version.
A20 Pro, thermal design, and the buying question
Apple says the iPhone 18 Pro Max uses the A20 Pro chip, built on a 2nm process, and a next-generation vapor chamber with three times the surface area of the previous iPhone 17 Pro design. The phone’s independent results show the outcome of the complete hardware and software package rather than a capacity figure alone.
For US buyers, the 256GB iPhone 18 Pro Max starts at $1,299. The practical battery verdict is straightforward: it led both cited independent comparisons, but the exact advantage depends on whether you are watching continuous video, running a maximum-brightness lab test, or using the phone in a different mix of apps, networks, and screen settings.
