What cable do I need for a 100 W laptop charger?
AnswerYes, if…
A USB-C to USB-C cable rated 5 A (sold as "100W" or "240W"). An ordinary 3 A cable caps the charger at 60 W, so the laptop still charges, just more slowly, and may drain under heavy load. Thunderbolt 3/4 and USB4 cables are 5 A, so they work too.
The power arithmetic
| Volts × amps | Watts | Cable needed |
|---|---|---|
| 20 V × 3 A | 60 W | Any USB-C to USB-C cable |
| 20 V × 5 A | 100 W | 5 A e-marked cable |
The 5 A rating lives in an e-marker chip in the plug, so two identical-looking cables can behave differently. Cables that say "60W" are 3 A. "100W" and "240W" cables are 5 A. If a laptop shows "slow charger" on a 100 W brick, swap the cable first.
The standards involved
2012
USB Power Delivery (60 W, 100 W, 240 W)
The charger and device agree a voltage; the cable decides whether 3 A or 5 A is safe.
- power: 60 W / 100 W / 240 W
Thunderbolt 4
The same 40 Gbps as Thunderbolt 3, with the minimums raised so every port behaves the same.
- data: 40 Gbps (PCIe 32 Gbps)
- video: two 4K 60 Hz or one 8K
- power: up to 100 W (USB PD)