Apple Watch Ultra 4 publishes three workout battery ratings: up to 18 hours of outdoor workout, up to 25 hours in Extended Workout mode, and up to 45 hours in a new Max Extended Workout mode that records GPS at one-second intervals. Apple aims that top mode at 100-mile races.
Training load sits on the other side of the event. It is one of the four inputs Apple names behind the daily Readiness score, alongside recent activity, vitals and sleep, and Apple has not published how any of it is calculated.
| Key fact | What Apple publishes |
|---|---|
| Normal use | Up to 50 hours, up to 84 in Low Power Mode |
| Outdoor workout | Up to 18 hours |
| Extended Workout | Up to 25 hours, 25 percent more than before |
| Max Extended Workout | Up to 45 hours with one-second GPS intervals |
| GPS | Precision dual-frequency, covering GPS, Galileo, QZSS and BeiDou |
| Charging | 80 percent in about 45 minutes, 15 minutes for up to 18 hours |
| Price and date | From $799, in stores September 18 |
Three workout tiers, and one of them is new
Outdoor workout is rated at up to 18 hours, against up to 10 hours on Apple Watch Series 12. Extended Workout mode reaches up to 25 hours, which Apple describes as 25 percent more than before. Max Extended Workout mode is the new one, at up to 45 hours.
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Away from workouts, Ultra 4 is rated for up to 50 hours of normal use and up to 84 hours in Low Power Mode, both up from the 42 and 72 hours Apple published for Ultra 3.
What each rating covers on a race day
The table below is our arithmetic against Apple’s published ratings, using common event lengths. The hours are Apple’s. The headroom column is ours, and Apple has not published the conditions its ratings assume.
| Event length | Lowest mode Apple rates as sufficient | Headroom |
|---|---|---|
| Marathon, about 4 hours | Outdoor workout, 18 hours | About 14 hours |
| 12-hour event | Outdoor workout, 18 hours | About 6 hours |
| 24-hour event | Extended Workout, 25 hours | About 1 hour |
| 100-mile race finished in 30 hours | Max Extended Workout, 45 hours | About 15 hours |
| Anything past 45 hours | None rated | Apple publishes no figure beyond 45 hours |
Two things follow from Apple’s own numbers rather than from any advice. A 24-hour event sits close to the Extended Workout rating, and the fast charge figure, 80 percent in about 45 minutes, is the only published route back if a mode runs out.
One-second GPS and the 100-mile target
Apple’s stated purpose for Max Extended Workout mode is 100-mile races, and the one detail it publishes about how the mode behaves is the one-second GPS interval. It has not published the intervals used in the other modes, so the figure has no published baseline to sit against.
The GPS hardware is the strongest Apple lists in the lineup. Ultra 4 uses precision dual-frequency GPS across GPS, Galileo, QZSS and BeiDou, and Apple calls it the most accurate on-device GPS in a sports watch. Series 12 uses precision L1 GPS across GPS, GLONASS, Galileo, QZSS and BeiDou.
Training load and the score it feeds
Training load is named, and that is close to all Apple says about it. It is one of four Readiness inputs, and the score it feeds runs from 0 to 10 with four recommendations attached: Recover, Pace Yourself, Ready and Go For It.
Apple has not published how training load is calculated, over what window, or how heavily it weighs against recent activity, vitals and sleep. Readiness is not a medical assessment, and Apple makes no clinical claim for it. What a given score means for your next session is a decision for you or your coach.
The rest of the long-day hardware
- Case: 49mm Grade 5 titanium in natural or black, 63.0g and 63.1g, for wrists from 130mm to 210mm.
- Display: always-on LTPO3 OLED at 422 x 514 pixels and 326 ppi, 3000 nits peak and 1 nit minimum, under flat sapphire.
- Durability: 100 meters under ISO 22810:2010, EN13319 recreational scuba to 40 meters, IP6X, tested to MIL-STD 810H, and rated on-wrist from minus 20 to 55 degrees Celsius.
- Communications: Emergency SOS, Messages and Find My via satellite, with two years included on Ultra 3 and later.
What Apple has not said
Apple has not published whether Max Extended Workout mode is chosen manually or entered automatically, what it turns off to reach 45 hours, or how the one-second GPS interval compares with the sampling in the other modes.
It has also not said whether the mode reaches Series 12, which is rated at up to 10 hours of outdoor workout and lists no extended tiers, and it has published no real-world results for any of the ratings. Nothing in the September 9 announcements added a figure beyond the ones above.
Apple Watch Ultra 4 reaches stores on Friday, September 18, from $799, with watchOS 27 arriving free on Monday, September 14 alongside iOS 27 and the redesigned Health app.
