The iPhone 17 Pro Max battery capacity is listed at 4823 mAh (about 18.7 Wh) in the physical SIM build and 5088 mAh (about 19.8 Wh) in the eSIM-only build. Apple does not print mAh on its own pages, so these figures come from regulatory filings and teardown listings, not from the maker. Apple's own claim for this phone is up to 39 hours of video playback.
Why two numbers? The phone is sold with different SIM arrangements, and most listings link the larger cell to the build with no SIM tray. If you want to plan around one number, use the lower one as the safe figure. The battery health screen on your own phone is the best way to see how much of the original capacity is left today.
Quick facts
Step by step
Open the battery health screen
Go to Settings, tap Battery, then open Battery Health. On some iOS versions it is called Battery Health & Charging.
Read the Maximum Capacity figure
The percentage next to Maximum Capacity compares your battery with its new state. A fresh phone shows 100 percent.
Look for any service message
If a message about the battery appears on this screen, note it down and show it at the service counter.
Check the charging options
In the battery settings, find the charging options and see whether Optimized Battery Charging is on. Menu names change between iOS versions, so type "charging" in the Settings search bar if you cannot find it. Leave it on for a phone that charges overnight.
Note the model number
Open Settings, General, About and write down the model number before you talk about parts or service.
iPhone 17 Pro Max battery capacity in mAh and Wh
The two builds carry two different listed figures. Watt hours is the fairer measure, because it already includes the cell voltage. To convert iPhone mAh to watt hours, multiply by the voltage and divide by a thousand.
| Build | Capacity | Voltage | Energy |
|---|---|---|---|
| Physical SIM | 4823 mAh | 3.887 V | 18.748 Wh |
| eSIM only | 5088 mAh | 3.886 V | 19.772 Wh |
These are listed values. Apple does not list iPhone mAh in its own documents, so the 17 Pro Max numbers come from filings and teardowns. A repair technician reading a label may see a slightly different rated number, and that is normal.
Why the phone shows two capacity figures
Most listings give the smaller cell to the build that keeps a physical SIM tray, because the tray and its housing take up room inside the body. The eSIM-only build has no tray, so the freed space appears to go to a larger cell. Apple has not explained this itself. The gap is about 265 mAh, which is roughly 5 percent.
In daily use you will not feel a 5 percent gap very much. A different screen brightness or a weak signal changes the day far more. Do not worry if a friend quotes the other number: both can be correct for different units. A SIM tray on the side of your phone points to the physical SIM build.
Before you compare capacity with a friend, ask whether their phone has a tray. It explains most disagreements.
iPhone 17 Pro Max battery mAh capacity against nearby models
The Pro Max has the largest battery in the current Pro line. The table puts it beside its closest relative and points to pages for the rest of the range.
| Phone | Listed capacity | Note |
|---|---|---|
| iPhone 17 Pro Max | 4823 or 5088 mAh | About 18.7 or 19.8 Wh |
| iPhone 17 Pro | 3988 or 4252 mAh | About 15.5 or 16.6 Wh, same two builds |
| iPhone 17 | See its page | Smaller body, different cell |
| iPhone 16 | See its page | Earlier base model |
| iPhone 15 | See its page | Older base model |
The Pro Max cell is roughly 20 percent larger than the Pro cell in the same build type. For every model in one place, open the iPhone capacity list.
What up to 39 hours of video means in real life
Apple's claim of up to 39 hours is a test figure for video playback under set conditions. Nobody uses a phone like that all day. Calls, maps, a camera, games and mobile data pull the number down quickly.
- Bright screen outdoors, especially at the highest brightness, drains fastest.
- Weak mobile signal makes the radio work harder, so a train or basement shortens the day.
- Games and long camera sessions heat the phone and use more power.
- An older cell with lower health holds less than the listed capacity.
A fresh Pro Max usually carries a heavy user through a full day, but your result will differ. If your 17 Pro Max drains much faster than friends' phones, read our drain guide before blaming the cell.
Charging speed and habits for a big cell
Charging time depends on the adapter and cable, not on mAh alone. Apple lists the supported charging speeds for this phone on its own support pages, so check there for the current figures instead of trusting a repeated number. A weak adapter will charge a large cell slowly, and a damaged cable can be slower still.
On a 17 Pro Max, heat and hours spent at 100 percent wear the cell down. Charge the 17 Pro Max out of direct sunlight, remove a heavy case when it warms, and keep Optimized Battery Charging switched on for nights. A bigger cell does not remove these rules; it only gives you more days before they matter.
The official page on battery and performance explains these settings in detail.
How to check battery health on this phone
iOS shows a health percentage for the iPhone 17 Pro Max under Settings, Battery, Battery Health. Some iOS versions name it Battery Health & Charging. That figure compares today's capacity with the capacity when new. Apple's wording for this figure is Maximum Capacity.
A new phone starts near 100 percent. A reading that slips only a little after a year of normal use is healthy. If you see a service message, or the phone shuts off while the percentage still looks fine, move to a proper test. The health check guide walks through the steps in order and tells you when the number matters.
An owner noticed the phone dropping from 30 percent to switch off during a cold morning commute. The health screen showed a high percentage, so she updated iOS, warmed the phone, and the problem stopped. Cold alone can cause this, so test again at normal room temperature before you worry.
When the cell needs a replacement
The iPhone 17 Pro Max is a sealed phone, so leave the opening to professionals. Apple's repair page lists the official route, and a trusted repair shop is another option. iPhone cells are matched to the exact phone, so give them the model number from About.
Swelling, strong heat, leaking or a dent make the 17 Pro Max cell dangerous. Unplug the 17 Pro Max, keep pressure off it, let it cool and book Apple service the same day. Cheap iPhone cells with inflated mAh labels are common, so accept only a part from Apple or an authorised provider.
Fitting is covered in more depth in our battery swap notes.
Frequently asked questions
What is the iPhone 17 Pro Max battery capacity in mAh?
Listings give 4823 mAh for the physical SIM build and 5088 mAh for the eSIM-only build. These come from filings and teardowns, because Apple does not give mAh on its own pages.
How many watt hours does the iPhone 17 Pro Max battery hold?
About 18.7 Wh for the 4823 mAh build and about 19.8 Wh for the 5088 mAh build. Watt hours are the better number to compare across phones.
Is the iPhone 17 Pro Max bigger than the iPhone 17 Pro in battery?
Yes. The Pro Max cell is listed at about 4823 or 5088 mAh, while the Pro is listed at about 3988 or 4252 mAh. Open the iPhone 17 Pro page for its own details.
How long does the iPhone 17 Pro Max battery last?
Apple claims up to 39 hours of video playback. In mixed daily use it usually lasts a full day, though signal, brightness and apps change the result.
Where is battery health on the iPhone 17 Pro Max?
Go to Settings, then Battery, then Battery Health. Some iOS versions call it Battery Health and Charging. The Maximum Capacity percentage compares your cell with a new one.
Can I swap the battery myself?
No. The 17 Pro Max is a sealed phone, and a punctured cell can ignite. Use Apple's service route or a trusted repair shop.