Can I use my phone's USB-C charger on my laptop?
Usually yes, if it is a USB Power Delivery charger and your laptop charges over USB-C. It is safe, because the two negotiate. But a phone charger often supplies fewer watts than a laptop wants, so it may charge slowly or only hold the level. Match the wattage on your original adapter and use a cable rated for it.
Cite
Geek With Laptop Forum, "Can I use my phone's USB-C charger on my laptop?", https://geekwithlaptop.com/forum/thread/can-i-use-my-phones-usb-c-charger-on-my-laptop/, accessed 2026-11-10.I am a student and I left my laptop charger at my sister's place two towns over. My laptop has a USB-C port on the left side with a little lightning bolt next to it, and the original charger ends in a USB-C cable too. I have a USB-C charger for my phone sitting right here, plus a second one from a tablet.
Can I just plug the laptop into one of those? I am not worried about it being slow for a day or two, I am worried about frying something. The phone charger is small and the original laptop one is a lot bigger, which makes me think they are not the same thing.
Also, if it works but charges really slowly, is that bad for the battery long term, or just annoying? And does it matter which cable I use? I have a few lying around and I have no idea which came with what.
- Accepted answerMarcus HaleStaffEditor, Geek With Laptop ·
Usually yes, if it is a USB Power Delivery charger and your laptop charges over USB-C. It is safe, because the two negotiate. But a phone charger often supplies fewer watts than a laptop wants, so it may charge slowly or only hold the level. Match the wattage on your original adapter and use a cable rated for it.
Kenji, here is the detail. The USB Implementers Forum describes Power Delivery as flexible power over one cable, where each device takes only the power it requires. Their page also notes that before the 3.1 revision, USB PD topped out at 100 watts at 20 volts over cables rated for 5 amps, and that newer higher voltage levels reach 240 watts. So wattage varies enormously between chargers, and the cable has to be rated for what is being carried. Source: USB Charger (USB Power Delivery), USB-IF.
Microsoft's Windows documentation lists the same causes for "slow charger" and "PC isn't charging" notices: the charger is not powerful enough, the cable does not meet the power requirements, the charger is in a port that does not charge, or it is connected through a hub or dock. It advises using the charger and cable that came with the PC, and connecting to the USB-C port that supports charging. Source: Fix USB-C problems in Windows, Microsoft Support.
Slow charging is mostly just slow, not a danger. A MacBook or Chromebook follows the same logic, though some models only charge on certain ports, so check the manual for yours. If the laptop reports a warning, believe it. Tyler, the plug being the same does not mean the power is the same, and the cable does matter.
5 more replies
Most helpful first- DmitriMember ·
It will not fry anything. USB-C chargers that follow the Power Delivery standard negotiate with the laptop before sending real power. The laptop asks, the charger says what it can offer, and they settle on a voltage and current. If the charger cannot offer enough, the usual outcome is slow charging or "plugged in, not charging". On Linux you can watch it in the terminal with upower -d, if you are into that.
- Grace O.Member ·
I look after six work laptops, so I have been through this with a drawer full of chargers. Two practical things. First, look at the fine print on the original charger. It lists a wattage, and that is the number to match or come close to. Second, the cable counts for higher wattages. A thin cable that is fine for a phone can be the weak link for a laptop.
We had one laptop that kept saying "plugged in, not charging" until we put the right charger back on it.
- Grace O.Member ·
@Tyler B. I would not go by that. It may have worked for you because the charger you used was strong enough. In our drawer, a phone-class charger on a bigger laptop gave "plugged in, not charging" at least once, and a thin cable was the cause when the charger itself was fine.
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