USB-C is a connector shape; what it does depends on the cable and the device. If your phone charges slowly—or your hard drive crawls—the wrong cable is usually the reason. Here’s the simple guide.

Charging: watts matter (and the e-marker chip)

• Up to 60W (20V/3A) – most phones, tablets, and many ultrabooks.
• Up to 100W (20V/5A) – larger laptops and docks.
• Up to 240W (USB Power Delivery EPR) – newer high-power laptops.

Cables rated above 3A normally include an e-marker chip that tells your charger/device it’s safe to pull more current. If your 100W charger is slow, your cable may be a 60W (3A) cable.

Data: not all USB-C is fast

If you only need phone charging, USB 2.0 is fine. For external SSDs or 4K displays, look for 10–40 Gbps.

USB-A to USB-C vs USB-C to USB-C

• USB-A → USB-C: Perfect for older chargers and cars. Usually 18–27W charging; data often USB 2.0 (480 Mbps).
• USB-C → USB-C: Best for fast charging and fast data. Needed for 60–240W USB-PD.

What about iPhone?

Modern iPhones with USB-C charge fastest with USB-C to USB-C and a USB-PD charger (20W+). They still charge with USB-A to USB-C—just slower.

Cable checklist before you buy

• Length: 3–6 ft for desks; 10 ft for couches. Longer can mean slower data and reduced charging if poorly made.
• Rating on the listing: Look for “60W” or “100W/240W” and “10 Gbps/40 Gbps” if you need speed.
• Braided + strain relief: lasts longer in cars and travel bags.
• e-Marker present for 5A / 100W+ cables.

Recommended picks

• USB-A → USB-C fast-charge cable – perfect for cars and legacy chargers.
• USB-C → USB-C 60–100W cable – the everyday workhorse.

Not sure which one you need? Message us with your device model and we’ll match the right cable. Contact The Perfect Part.