Apple 140W USB-C Power Adapter on a MacBook Air: Measured
Apple's 140W USB-C adapter measured on a MacBook Air: a 94 W contract at 4.7 A. The full 140 W requires an EPR-capable Mac.
Apple’s 140W USB-C power adapter, tested against a MacBook Air with a low battery, per the methodology.
The numbers
| Rated | 140 W |
| Negotiated | 94 W (20 V up to 4.7 A) |
| Live draw | 69.9 W (20.1 V at 3.48 A) |
| Protocol | USB PD 3.0 |
Profile menu: 15 W (5 V up to 3 A), 27 W (9 V up to 3 A), 45 W (15 V up to 3 A), 94 W (20 V up to 4.7 A), 140 W (28 V up to 5 A).
EPR and the 28 V rail
This is Apple’s first charger to support the USB PD 3.1 Extended Power Range (EPR) specification, which allows it to push beyond the old 100 W limit of USB-C by increasing the voltage to 28 V.
However, because the MacBook Air is a standard (non-EPR) USB-C device, it cannot negotiate the 28 V rail. Instead, it safely falls back to the highest standard profile available: 94 W (20 V at 4.7 A). To actually see the 140 W profile become active, you need a 16-inch MacBook Pro that specifically supports EPR charging.
A 5A cable requirement
Even the fallback 94 W profile negotiates at 4.7 A. Because this exceeds the 3 A limit of a standard USB-C cable, a 5A (100W+) e-marked cable is strictly required to get past 60 W on this adapter. If you use a standard 3A cable, the adapter will only advertise up to 60 W, and that’s all your Mac will negotiate.
Buying one
The Apple 140W USB-C Power Adapter is the only Apple brick that exceeds 100 W, but the full 140 W (28 V EPR) is unlocked only by a 16-inch MacBook Pro. On any other Mac it tops out at 94 W, and it always needs a 5A cable.
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