The Galaxy Z Fold8 Ultra has a 5,000 mAh battery and the Galaxy Z Fold8 has a 4,800 mAh battery. In Tom’s Guide’s tests, both outlast the Galaxy Z Fold7. The Ultra lasted 14 hours 9 minutes, the Fold8 12 hours 20 minutes and the Fold7 10 hours 44 minutes. “Longest-lasting Folds yet” is a comparison inside Samsung’s own Fold line. It does not make either phone the longest-lasting foldable: the same Tom’s Guide table puts the Motorola Razr Fold ahead of the Ultra.
What Samsung actually says about the batteries
Samsung’s July 22, 2026 announcement describes the two phones this way: “Galaxy Z Fold8 Ultra is built for all-day productivity with a larger 5,000 mAh battery, while Galaxy Z Fold8 is equipped with a 4,800 mAh battery designed to deliver lasting power for immersive viewing and responsive performance.” It also says the Ultra has a dual-path charging architecture and 45 W fast charging.
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The wording is about capacity, and it is not a claim about runtime against other brands. Sales began in select markets on August 7, 2026, and the rollout is expanding globally, so availability depends on your region.
Advertised capacity versus rated capacity
The 4,800 mAh figure for the Fold8 is the advertised, or typical, capacity. Samsung’s product-information footnote gives the Fold8’s rated capacity as 4,660 mAh. Samsung says typical capacity is estimated from tested battery samples under IEC 61960. These are two different numbers for the same battery, so check which one a spec sheet or comparison is quoting. I did not find a rated figure for the Ultra in the material reviewed, so don’t assume the same gap applies to it.
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Samsung’s video-playback estimate for the Fold8 comes from internal testing on a pre-release device. The setup was Bluetooth earphones, default settings, LTE, and a locally stored 720p file on the main screen. Samsung notes that real-world time varies with network, settings, file format, brightness and battery condition. Treat it as a best-case playback figure and not as a mixed-use estimate.
Measured battery life
Tom’s Guide’s dedicated comparison
| Phone | Battery test time | Difference vs Fold7 |
|---|---|---|
| Motorola Razr Fold | 14 h 44 min | +4 h 0 min |
| Galaxy Z Fold8 Ultra | 14 h 9 min | +3 h 25 min (about 32%) |
| Galaxy Z Fold8 | 12 h 20 min | +1 h 36 min (about 15%) |
| Galaxy Z Fold7 | 10 h 44 min | baseline |
The differences are my arithmetic from Tom’s Guide’s published times. On these numbers the Ultra lasts about 1 hour 49 minutes longer than the standard Fold8, and the Razr Fold beats the Ultra by 35 minutes.
Rank #2
- SPLIT THE VIEW. MULTITASK¹ TO THE MAX: Productivity never felt this powerful. Use up to three apps¹ at once on the expansive inner screen of Galaxy Z Fold8 Ultra. You’ll enjoy plenty of space to work, play, connect and more.
- MULTITASKING MADE SMARTER WITH AI: Stay one step ahead with AI² that suggests which apps you might need next. Then view those multiple windows side by side on the large screen of your Galaxy Z Fold8 Ultra.
- ANY SHOT, ALL THE DETAILS: Dive into the details of any image with our best camera on a foldable smartphone. Galaxy Z Fold8 Ultra boasts a 200MP camera — and an upgraded 50MP Ultra Wide lens — for both stunning wide shots and extreme close-ups.
- ELITE CHIPSET. FLUID GRAPHICS: Experience what’s possible with our most advanced Galaxy Z Series processor. From immersive gaming and speedy multitasking to the latest Galaxy AI³ features, the Snapdragon 8 Elite Gen 5 keeps everything running seamlessly.
- THE BATTERY YOU’VE BEEN WAITING FOR: It’s the battery you’ve been wanting in a foldable cell phone. Galaxy Z Fold8 Ultra packs a powerful ultra-sized⁴ battery in an ultra-slim design. Plus, with Super Fast Charging 2.0⁵, charge up faster than ever before.
A second Tom’s Guide report gives different Ultra numbers
Tom’s Guide’s separate Fold8 review reports a 5G web-surfing test. In it the Fold8 lasted 12 hours 19 minutes and the Ultra 14 hours 33 minutes. The Fold8 figure is within a minute of the comparison chart. The Ultra figure is 24 minutes higher than the chart’s 14:09. Both are published results, so they are best read as a range of roughly 14 to 14.5 hours for the Ultra under that outlet’s testing. I have not averaged them or picked one. No standardized cross-site result exists in the sources reviewed.
Is the Ultra’s battery better than the standard Fold8’s?
On both capacity and measured runtime, yes. The Ultra’s 5,000 mAh is about 4% larger than the Fold8’s 4,800 mAh. The measured gap in both Tom’s Guide reports is larger than that, about 15% in the chart and about 18% in the review. The sources don’t say why, and I won’t guess whether processor, display or software tuning accounts for it. The practical result is that the Ultra gave you roughly 1 hour 50 minutes to 2 hours 15 minutes more in those tests.
Rank #3
- CREATED FOR YOUR CONTENT: Any way you turn it, the new Galaxy Z Fold8 gives you a fuller viewing experience. Designed with your content in mind, this foldable phone is the perfect size to make your movies, books and more incredibly immersive.
- WORLD’S LIGHTEST FOLD¹: Galaxy Z Fold8 is the newest foldable phone for content on the go. Unfolded, it fits movies and books for an immersive experience. Folded, it delivers comfortable texting and everyday use — all on the world’s lightest fold.¹
- THE BRIGHTEST DISPLAY ON A GALAXY PHONE: Our brightest smartphone display² provides you with a comfortable view, whether you’re inside or outside. Watch movies, play games and scroll with ease no matter where you are.
- RECORD. REFRAME. READY FOR SOCIAL³: Record content on Galaxy Z Fold8 and then use My FanCam³ to keep your subject center stage. The result is a social-ready video that focuses on the part of the action you really want.
- UNTETHER YOUR ENTERTAINMENT: The long-lasting battery of Galaxy Z Fold8 is built to power hours of entertainment. And when you do need to recharge, Super Fast Charging 2.0⁴ gets you back to what you love quickly.
The standard Fold8 is not a weak battery. In the same comparison it lasted about an hour and a half longer than the Fold7.
Charging speed
In Tom’s Guide’s dedicated comparison, the phones charged as follows:
Rank #4
- SPLIT THE VIEW. MULTITASK¹ TO THE MAX: Productivity never felt this powerful. Use up to three apps¹ at once on the expansive inner screen of Galaxy Z Fold8 Ultra. You’ll enjoy plenty of space to work, play, connect and more.
- MULTITASKING MADE SMARTER WITH AI: Stay one step ahead with AI² that suggests which apps you might need next. Then view those multiple windows side by side on the large screen of your Galaxy Z Fold8 Ultra.
- ANY SHOT, ALL THE DETAILS: Dive into the details of any image with our best camera on a foldable smartphone. Galaxy Z Fold8 Ultra boasts a 200MP camera — and an upgraded 50MP Ultra Wide lens — for both stunning wide shots and extreme close-ups.
- ELITE CHIPSET. FLUID GRAPHICS: Experience what’s possible with our most advanced Galaxy Z Series processor. From immersive gaming and speedy multitasking to the latest Galaxy AI³ features, the Snapdragon 8 Elite Gen 5 keeps everything running seamlessly.
- THE BATTERY YOU’VE BEEN WAITING FOR: It’s the battery you’ve been wanting in a foldable cell phone. Galaxy Z Fold8 Ultra packs a powerful ultra-sized⁴ battery in an ultra-slim design. Plus, with Super Fast Charging 2.0⁵, charge up faster than ever before.
| Phone | After 15 minutes | After 30 minutes |
|---|---|---|
| Galaxy Z Fold8 Ultra | 49% | 76% |
| Galaxy Z Fold8 | 43% | 70% |
These are one outlet’s results and will vary with the charger and conditions. Samsung’s stated 45 W charging for the Ultra implies you need a compatible 45 W USB-C charger. Whether a charger is in the box differs by region and was not established, so check the listing for your market before buying one separately.
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How to read “longest-lasting Folds yet”
- Within the Fold line: supported. Both Fold8 models beat the Fold7 in Tom’s Guide’s test, and the Ultra leads the Fold8.
- Across foldables: not supported. The Razr Fold lasted longer than the Ultra in the same table.
- Over time: unknown. The sources reviewed don’t cover long-term battery aging or replacement costs.
- Your own use: will differ. Outlet tests use fixed brightness and tasks, and heavy gaming, 5G in weak coverage or a lot of time on the inner screen will usually cut the numbers.
Which one to choose for battery life
Choose the Ultra if you often go a full day away from a charger, since it has the larger battery, the longest runtime of the two and the faster charging in the tests. The standard Fold8 is a sensible pick if the other differences matter more to you, because its battery is still a clear step up from the Fold7. If battery runtime alone decides it, the Razr Fold tested ahead of both Samsung models.
Quick Recap
Best Value
- CREATED FOR YOUR CONTENT: Any way you turn it, the new Galaxy Z Fold8 gives you a fuller viewing experience. Designed with your content in mind, this foldable phone is the perfect size to make your movies, books and more incredibly immersive.
- WORLD’S LIGHTEST FOLD¹: Galaxy Z Fold8 is the newest foldable phone for content on the go. Unfolded, it fits movies and books for an immersive experience. Folded, it delivers comfortable texting and everyday use — all on the world’s lightest fold.¹
- THE BRIGHTEST DISPLAY ON A GALAXY PHONE: Our brightest smartphone display² provides you with a comfortable view, whether you’re inside or outside. Watch movies, play games and scroll with ease no matter where you are.
- RECORD. REFRAME. READY FOR SOCIAL³: Record content on Galaxy Z Fold8 and then use My FanCam³ to keep your subject center stage. The result is a social-ready video that focuses on the part of the action you really want.
- UNTETHER YOUR ENTERTAINMENT: The long-lasting battery of Galaxy Z Fold8 is built to power hours of entertainment. And when you do need to recharge, Super Fast Charging 2.0⁴ gets you back to what you love quickly.
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