We’re getting close to the official unveiling of the next iPhone generation and, as usually happens around this time of year, a few more pieces of the puzzle are starting to fall into place.
If the latest leaks are accurate, the iPhone 18 Pro Max could arrive with a considerably larger battery, while the iPhone 18 Pro may get a much more modest upgrade.
And that could make choosing between the two models a little more complicated for anyone who cares a lot about battery life.
The Pro Max could get the biggest battery boost
Information found in regulatory filings in China points to two different battery capacities, depending on the version of the device, either with a physical SIM slot or eSIM only.
For the iPhone 18 Pro, the reported figures are:
- 4,056 mAh for the version with a physical SIM slot
- 4,288 mAh for the eSIM-only version
The iPhone 18 Pro Max, meanwhile, could come with:
- 5,391 mAh for the version with a physical SIM slot
- 5,567 mAh for the eSIM-only version
The difference becomes even more interesting when we compare those numbers with the current generation.
| (Models with physical SIM) | iPhone 17 | iPhone 18 |
| Pro model | 3,988 mAh | 4,056 mAh |
| Pro Max model | 4,823 mAh | 5,391 mAh |
The iPhone 17 Pro has a 3,988 mAh or 4,252 mAh battery, depending on the version. The iPhone 17 Pro Max, meanwhile, uses 4,823 mAh or 5,088 mAh batteries.
In other words, the expected increase for the smaller Pro model is fairly modest, at roughly 1% to 2%.
With the Pro Max, however, it’s a very different story.
Depending on which versions are compared, the increase could range from roughly 9% to 12%. At the highest capacity, we’re talking about nearly 500 mAh more from one generation to the next.
For an iPhone battery, that’s a significant jump.
The gap between the Pro and Pro Max could become huge
Another interesting detail emerges when we put the two upcoming models side by side.
If these capacities are confirmed, the iPhone 18 Pro Max could have a battery around 30% larger than the one inside the iPhone 18 Pro.
That’s a substantial difference.
Today, anyone choosing the Pro Max already knows they’re getting a larger phone, a bigger display, and better battery life. But with this generation, battery life could become an even more important factor in the buying decision.
That doesn’t mean, of course, that the Pro Max will automatically deliver 30% longer battery life.
The larger display also consumes more power. Brightness, processing, the modem, cameras, and even the way the operating system behaves can all have a major impact on real-world battery life.
Even so, there is a physical advantage that can’t be ignored. Put a much larger battery inside the phone, and there is real potential to spend considerably more time away from a charger.
The new chip could help even more
And the battery won’t be doing all the work on its own.
The iPhone 18 Pro models are expected to use the new A20 Pro chip, manufactured using TSMC’s 2-nanometer process.
That change should primarily improve power efficiency. Put simply, the goal is to get more work done while using less energy.
This is where the Pro Max could become especially interesting.
While the iPhone 18 Pro may rely heavily on the efficiency gains of the new chip to improve battery life, the Pro Max could combine both advantages: a more efficient processor and a significantly larger battery.
If that happens, it wouldn’t be surprising to see Apple once again highlight battery life as one of the biggest advantages of the larger model.
But it may also get a little heavier
There is, naturally, a price to pay for putting a larger battery inside the phone.
Recent rumors suggest that the iPhone 18 Pro Max could become slightly thicker and heavier, measuring close to 9 mm thick and weighing around 240 grams.
Part of that could be directly related to the larger battery.
There have also been reports of changes to the internal heat dissipation system, which could take up additional space inside the device.
If all of this turns out to be true, it would represent an interesting choice by Apple.
For many years, the company pushed toward making its devices thinner and thinner. Now, at least with the model aimed at people who want the best performance and battery life possible, Apple seems more willing to accept a few extra grams in exchange for a bigger battery.
And for a lot of people, that tradeoff will probably make sense.
The exact numbers still don’t agree
It’s worth remembering that these capacities have not yet been confirmed by Apple.
Earlier reports pointed to 5,235 mAh and 5,425 mAh batteries for the iPhone 18 Pro Max. Later, regulatory filings surfaced with slightly higher figures of 5,391 mAh and 5,567 mAh.
So the final capacity figures could still change.
But there is one thing the different leaks have in common: they all suggest that the Pro Max will receive a much more substantial battery upgrade than the smaller Pro model.
And that may be the most important takeaway for now.
We should have the answer in September, when Apple officially unveils the new generation.
