What Is USB 3.0?

USB 3.0 details and connector information

Photo of a USB 3.0 Type A to Micro-B Cable

Cable Matters

USB 3.0 is a Universal Serial Bus (USB) standard, released in November 2008. Most new computers and devices being manufactured today support USB 3.0. USB 3.0 is often referred to as SuperSpeed USB.

Devices that adhere to the USB 3.0 standard can theoretically transmit data at a maximum rate of 5 Gbps, or 5,120 Mbps. This is in stark contrast to previous USB standards, like USB 2.0, that at best can only transmit data at 480 Mbps or USB 1.1 that tops out at 12 Mbps.

USB 3.2 is an updated version of USB 3.1 (SuperSpeed+) and is the latest USB standard. It increases this theoretical maximum speed to 20 Gbps (20,480 Mbps), while USB 3.1 comes in at a maximum speed of 10 Gbps (10,240 Mbps).

Older USB devices, cables, and adapters may be physically compatible with USB 3.0 hardware but if you need the fastest possible data transmission rate, all devices must support USB 3.0.


What is USB 3.0?

USB 3.0 Connectors

The male connector on a USB 3.0 cable or flash drive is called the plug. The female connector on the USB 3.0 computer port, extension cable, or device is called the receptacle.

  • USB Type A: These connectors, officially referred to as USB 3.0 Standard-A, are the simple rectangular type of USB connectors, like the plug at the end of a flash drive. USB 3.0 Type A plugs and receptacles are physically compatible with those from USB 2.0 and USB 1.1.
  • USB Type B: These connectors, officially referred to as USB 3.0 Standard-B and USB 3.0 Powered-B, are square with a large notch on top and are usually found on printers and other large devices. USB 3.0 Type B plugs are not compatible with Type B receptacles from older USB standards but plugs from those older standards are compatible with USB 3.0 Type B receptacles.
  • USB Micro-A: USB 3.0 Micro-A connectors are rectangular, "two-part" plugs and are found on many smartphones and similar portable devices. USB 3.0 Micro-A plugs are only compatible with USB 3.0 Micro-AB receptacles but older USB 2.0 Micro-A plugs will work in USB 3.0 Micro-AB receptacles.
  • USB Micro-B: USB 3.0 Micro-B connectors look very similar to their Micro-A counterparts and are found on similar devices. USB 3.0 Micro-B plugs are compatible with USB 3.0 Micro-B receptacles and USB 3.0 Micro-AB receptacles only. Older USB 2.0 Micro B plugs are also physically compatible with both USB 3.0 Micro-B and USB 3.0 Micro-AB receptacles.

    The USB 2.0 specification includes USB Mini-A and USB Mini-B plugs, as well as USB Mini-B and USB Mini-AB receptacles, but USB 3.0 does not support these connectors. If you encounter these connectors, they must be USB 2.0 connectors.

    Not sure if a device, cable, or port is USB 3.0? A good indication of USB 3.0 compliance is when the plastic surrounding the plug or receptacle is the color blue. While it's not required, the USB 3.0 specification recommends the color blue to distinguish cables from those designed for USB 2.0.

    You can view a USB physical compatibility chart for a one-page reference for what-fits-with-what.