Apple 40W Dynamic Power Adapter (60W Max) on a MacBook Air: Measured
Apple's 40W Dynamic Power Adapter measured on a MacBook Air M5: it starts at its 40 W guaranteed level, steps up to a 60 W peak, and the Mac takes the peak.
The Apple 40W Dynamic Power Adapter with 60W Max - a charger that puts two different wattages on its own label. Tested against a MacBook Air M5 with a low battery, per the methodology .
The numbers
| Rated | 40 W sustained / 60 W max |
| Negotiated | 60 W (20 V up to 3 A) - DPS |
| Live draw | 56.1 W (19.3 V at 2.91 A) |
| Protocol | USB PD 3.0 |
Profile menu:
| Profile | Rail |
|---|---|
| 15 W | 5 V up to 3 A |
| 27 W | 9 V up to 3 A |
| 40 W | 20 V up to 2 A |
| 45 W | 15 V up to 3 A |
| 60 W | 20 V up to 3 A - (DPS) |
The charger itself sends four fixed rails: 5, 9, 15 and 20 V, all at up to 3 A once it’s at its peak. The 40 W line is added by USB Connection Information, so both of the charger’s ratings are visible at once.
What DPS actually means
DPS is Dynamic Power Supply, the name the USB Power Delivery 3.2 specification has used since its August 2026 revision. The October 2024 change notice that introduced it called it a Dynamic Power Source. Either way, it’s a charger that guarantees one power level and offers a higher one while it’s cool enough. More in What DPS means on a USB-C charger .
This adapter guarantees 40 W and offers 60 W when conditions allow. It doesn’t list both at once. It offers one 20 V rung at a time: plugged in, it starts at 20 V and 2 A, which is 40 W, then raises the same rung to 3 A, which is 60 W. The Mac took the 60 W and settled at 56.1 W live.
Under sustained heavy load the adapter can step back to its 40 W level. That’s the design working, not the charger underperforming.
It’s a genuinely clever piece of engineering for a travel charger: near-60 W performance when the laptop is hungry, in a body sized for 40 W duty.
Reading it in the app
The charger only ever shows one 20 V rung, so USB Connection Information adds the other and marks the peak (DPS). That way you see both ratings together, and a list with 40 W and 60 W on the same 20 V rail reads as two levels of one charger, not a contradiction.
Buying one
The Apple 40W Dynamic Power Adapter (60W Max) is the current compact Apple adapter and a sensible default for a MacBook Air - small enough to travel with, and capable of real charging speed rather than a trickle.
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