Quick answer: USB-A is the old rectangular plug that only goes in one way and usually charges at 12W to 18W. USB-C is the small oval plug that goes in either way up, carries up to 240W with Power Delivery, and handles fast data and video. New laptops, phones and tablets use USB-C. USB-A is still useful for older accessories, which is why most chargers keep one USB-A port.
If you have bought any electronics in the last few years, you have noticed the shift. New laptops, phones and tablets are dropping the rectangular USB-A port in favour of the smaller, oval USB-C port. But plenty of older devices still use USB-A, and most chargers still include at least one USB-A port. Understanding the difference helps you buy the right cables, chargers and accessories without guessing.
The Physical Difference
The most obvious difference is the shape. USB-A is the rectangular connector that has been on computers and chargers since 1996. It only inserts one way, which is why you always seem to try it the wrong way first. USB-C is the smaller, oval connector introduced in 2014. It is symmetrical, so it inserts correctly either way up.
USB-C is also much smaller, which is why it fits in thin devices like the MacBook Air, iPad and modern Android phones, where a USB-A port would be too large.
The Performance Difference
The shape is the least important part. The real difference is in what each connector can do:
| USB-A | USB-C | |
|---|---|---|
| Charging power | Usually 12W to 18W; up to about 60W with some brands' own fast charging | Up to 240W (USB Power Delivery 3.1) |
| Max data transfer | Up to 10Gbps (USB 3.2) | Up to 40Gbps (USB4 and Thunderbolt 4) |
| Video output | No (needs an adapter) | Yes (DisplayPort or HDMI through Alt Mode) |
| Reversible | No | Yes |
| Laptop charging | Not standard | Yes (the Power Delivery standard) |
Why USB-C Is Taking Over
USB-C is not just a different shape. It is a more capable connector. The USB Power Delivery (PD) standard, set by the USB Implementers Forum, is what lets a charger run a laptop, and it only works over USB-C. The Thunderbolt 4 and USB4 standards behind 40Gbps data and 8K video also only work over USB-C. None of this is possible with USB-A.
With Power Delivery, the charger and the device agree on the right power level before charging starts. A phone plugged into a 140W port still only draws what the phone can take, so one USB-C charger can safely run your laptop, tablet and phone.
The European Union made USB-C the common charging standard for new phones, tablets and laptops sold in Europe from 2024. Apple moved the iPhone to USB-C with iPhone 15 in 2023. For new devices, the switch is effectively done.
Does USB-A Still Matter?
Yes, for now. Plenty of devices still use USB-A for charging or data: older phones, keyboards, mice, game controllers, some earbuds and a wide range of accessories. A USB-A port on a charger saves you an adapter for all of these.
Most of our chargers keep at least one USB-A port for exactly this reason. The Zeus 280W has 3 USB-C ports and 1 USB-A port. The Omega 200W has 2 USB-C and 2 USB-A. Either covers your current USB-C devices and your older USB-A accessories from one charger.
USB-C Cables Are Not All the Same
This is the most important thing to know when buying USB-C cables. The plug shape is standard, but what the cable can carry varies a lot:
- Basic USB-C cables: charge at up to 60W and move data at USB 2.0 speed (480Mbps). Fine for phones, not for most laptops.
- E-Mark cables: have a small chip that tells the charger and device what the cable can handle. Needed for reliable charging above 60W. Our 240W USB-C cable is E-Mark certified.
- Thunderbolt and USB4 cables: support up to 40Gbps data and 8K video. Needed for external monitors or fast storage.
A USB-C cable that came with a cheap phone charger will not reliably charge a MacBook Pro at 140W, even though it fits. The plug is the same. What the cable can carry is not.
Quick rule: to charge a laptop, use a cable rated for the wattage you need, with an E-Mark chip. For data above 5Gbps, check the cable's rated speed. The plug shape alone tells you nothing about what the cable can do.
Vinson is Cofounder at Chargeasap, an Australian charging hardware company that has run 14 crowdfunding campaigns on Kickstarter and Indiegogo and shipped to more than 108,000 customers since 2016.
FAQ
What is the difference between USB-A and USB-C?
USB-A is the older rectangular connector found on most computers and chargers. USB-C is the newer, smaller, oval connector that goes in either way up and supports much higher charging power (up to 240W) and data speeds (up to 40Gbps). USB-C is now the standard on new laptops, phones and tablets.
Can I use a USB-C cable in a USB-A port?
Not directly. You need a cable with USB-A on one end and USB-C on the other, or an adapter. Charging through USB-A is limited to what that USB-A port can supply, usually 12W to 18W.
Is USB-C faster than USB-A for charging?
Yes. USB-C with Power Delivery supports up to 240W, which is what laptops need. A standard USB-A port gives 12W to 18W, and even brand-specific fast charging over USB-A rarely goes past about 60W. For phones the gap is smaller, but USB-C PD still charges most modern phones faster.
Do all USB-C cables support fast charging?
No. Basic USB-C cables carry up to 60W. Cables with an E-Mark chip carry 100W or more. Check the cable's rated wattage before you use it to charge a laptop: an underpowered cable means slow charging or none at all.
