The Galaxy S25 Ultra is shaping out to be a beast after we’ve put it through some testing. Not only does it have the brightest screen we’ve tested in a Samsung phone to date, but it just achieved a record-setting mark for battery life among Samsung phones we’ve tested — and all other phone releases this year can’t afford to come up short.
Most successive phones usually get larger size batteries to extend their battery life performance over their predecessors. However, Samsung has chosen to keep the same sized 5,000 mAh battery as before. That means a lot falls on its new chipset, the Snapdragon 8 Elite, which has already proven itself to be extremely power efficient.
However, the S25 Ultra's ultra-long battery life does come with a caveat. So read on to find out what that is, and how the Galaxy S25 Ultra fares against the iPhone 16 Pro Max as well as some of its direct rivals on our list of the phones with the best battery life.
| Row 0 - Cell 0 | Battery Size (mAh) | Battery life (hours:mins) |
| Galaxy S25 Ultra | 5,000 mAh | 17:15 |
| Galaxy S24 Ultra | 5,000 mAh | 16:45 |
| iPhone 16 Pro Max | 4685 mAh | 17:35 |
| Asus ROG Phone 9 Pro | 5,800 mAh | 20:34 |
| OnePlus 13 | 6,000 mAh | 19:45 |
| Pixel 9 Pro XL | 5,060 mAh | 12:54 |
The Galaxy S25 Ultra clocked in at 17 hours and 15 minutes during our testing, making it the longest-lasting Samsung phone we’ve tested to date. In contrast, the Galaxy S24 Ultra with exactly the same 5,000 mAh battery capacity tapped out at 16 hours and 45 minutes. This turns out to be an improvement of 30 minutes, or roughly a 3% boost, which doesn’t sound all that dramatic.
However, it’s worth pointing out that these results come from using their adaptive modes — where the display refresh rate will automatically change depending on what’s shown on screen. When we set it to standard mode, which maxes out the refresh rate to 60Hz, the S25 Ultra got an even better time of 18 hours and 35 minutes. That’s an improvement of nearly 15% over the Galaxy S24 Ultra’s time of 16 hours and 11 minutes.
As much as we applaud Samsung for getting more juice out of the same sized battery, it falls short against other recent phones powered by the same Snapdragon 8 Elite chip. For example, the OnePlus 13 reaches an epic 19 hours and 45 minutes, while the Asus Rog Phone 9 Pro goes for even longer at 20 hours and 34 minutes. Again, these results come from their default auto refresh rate modes.
The iPhone 16 Pro Max, our current best phone leader, clocks in at 17 hours and 35 minutes with its adaptive refresh rate — so it technically beats the Galaxy S25 Ultra.
| Row 0 - Cell 0 | Wired Charging Speed | Charge % after 30 minutes |
| Galaxy S25 Ultra | 45W | 71% |
| Galaxy S24 Ultra | 45W | 71% |
| iPhone 16 Pro Max | 30W | 55% |
| Asus ROG Phone 9 Pro | 65W | 74% |
| OnePlus 13 | 80W | 92% |
| Pixel 9 Pro XL | 37W | 63% |
We’ll also briefly touch up on the Galaxy S25 Ultra’s recharging speed, which sees no improvement as it remains at 45W. Despite this, it manages to reach 71% battery capacity with 30 minutes of charging. Even with no updates, it's still one of the fastest charging phones we’ve tested. Only the Asus Rog Phone 9 Pro and OnePlus 13 beat it.
The bottom line here is that the Galaxy S25 Ultra’s battery life performance is a minor improvement, which means that there’s going to be more pressure for the Galaxy S26 Ultra next year. As much as the Snapdragon 8 Elite for Galaxy optimizes its battery life, it makes us wonder if Samsung will explore new battery technologies — like the long rumored stacked battery. However, Samsung still needs credit here because we’re dealing with a phone that has the same 5,000 mAh battery, but with a slightly larger 6.9-inch AMOLED display.
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