USB-C Explained: What It Is and Why You Want It

USB Type-C Connector

USB Type-C Connector

What Is USB-C?

USB-C is the latest USB (Universal Serial Bus) connector system. Also known as USB Type-C, it is distinguishable by its symmetrical and oval shape. USB-C itself is only a type of connector. Any given USB-C port does not necessarily support USB 3.1 or USB Power Delivery. The connector is common to several technologies. And it is those technologies that dictate what functions are available.

The USB Type-C 1.0 specification was finalized in September 2014. It started appearing on a significant number of consumer electronics in 2015-2016. Since then it has appeared on an increasing number of devices.

USB-C vs Legacy USB Connection Types

USB Legacy Connectors

USB Legacy Connectors

USB Type-C is the newest type of USB connector. Many legacy connectors are still in use today and often more recognizable.

  • USB-A: What most of us envision when we think “USB.”
  • USB-B: Found on USB printers, USB 2.0 external hard drives, and similar devices that receive data. There is a USB 1.1/2.0 version and a larger USB 3.0 version.
  • USB mini-B: The original miniaturized USB port. They were deprecated in 2007 and replaced by micro-B.
  • USB micro-B: Smaller than the mini ports, they are still produced today. Often used instead of USB-C for devices that don’t need as much power or data transfer speed.

It can replace all the above connectors. And supports newer, fast data transfer and power charging technologies. But it costs more to produce. As do its associated data transfer and fast charging technologies. A computer’s USB-C 3.1 connection costs 4-10 times more than a USB-A 2.0 connection. And a USB-C 3.1 Gen 2 connection costs 7 times as much as a USB-A 3.0 connection. Faster data rates aren’t worth the added cost for all customers. So older USB connectors and their technologies will stick around for a while longer.

USB Type-C is also reversible. You can plug in a USB Type-C cable in either orientation. Whereas all the legacy connections only work in one orientation. No more plugging it in, doesn’t fit, flip it, and plug it in again.

USB-C and Power

The most common use for USB-C on consumer devices is charging. Older USB connections also supported charging devices. But the latest phones and mobile devices need more power than older tech can provide.

Regular USB-C

All USB-C connections support (or should support) up to 15W power output/input. This is built into the spec and doesn’t need extra technology. It is not considered a fast-charging standard, though it is faster than most USB-A chargers.

USB Power Delivery

USB Power Delivery (USB PD) is an open standard, fast charging technology. Created alongside USB-C and maintained by the USB Implementors Forum. All USB PD is USB-C, but not all USB-C is USB PD. It allows for 15-100W, powering everything from a phone to a large gaming laptop.

Qualcomm Quick Charge 4+

Qualcomm’s Quick Charge 4+ operates exclusively over USB-C. It is spec-compliant (unlike QC 3.0) and works alongside USB Power Delivery. A QC 4+ charger can act as a USB PD charger. And a QC 4+ device can fast charge from a USB PD charger.

Quick Charge 3.0, Anker Power IQ, Samsung Fast Adaptive Charging, Huawei SuperCharge, and more

Many other fast charging standards, both new and old, are available on a variety of USB-C devices. They are not compliant with USB Type-C specs. And are proprietary technology. But they work without issue in the real world, provided the charger and device share the same technology.

Learn more about USB Fast Charging.

USB-C and Data Transfer

Like older USB connectors, USB-C supports a variety of USB standards. Those are interface technology, handling data transfers between two devices. This is completely separate from power. The different standards impact how fast your data transfer can be. All USB standards are backward compatible. For example, a USB 3.1 cable will support a USB 2.0 connection.

Legacy USB Standards

USB standards have been around since 1998. But thanks to its backward compatibility these are still supported by the newest connector.

USB 1.1

  • Data rates of 1.5-12 Mbps.
  • Commonly found on input devices, such as keyboards and mice.
  • Supported by most USB-C ports and cables.

USB 2.0

  • Data rate up to 480Mbps. Slow by today’s standards.
  • The likely standard is found if your device doesn’t specify.
  • Supported by most USB-C ports and cables.

USB 3.0

  • Data rate up to 5Gbps.
  • Supported by some USB-C ports but under a new name: USB 3.1.

USB 3.1

USB 3.0 was renamed USB 3.1 when USB-C was released. Afterward, the second version of USB 3.1 was added. Technically USB 3.0 refers to USB-A connections and USB 3.1 refers to Type-C connections.

  • USB 3.1 Gen 1: Data rate up to 5Gbps. The same as USB 3.0, but renamed.
  • USB 3.1 Gen 2: Data rate up to 10Gbps.

USB 3.2

USB 3.2 is the current version of USB standards. It absorbed the two USB 3.1 standards above and renamed them (again). It also added two new standards that use multi-lane technology.

  • USB 3.2 Gen 1×1: Data rate up to 5Gbps. Same as USB 3.0 and USB 3.1 Gen 1.
  • USB 3.2 Gen 1×2: Data rate up to 10Gbps. Uses new dual-lane tech.
  • USB 3.2 Gen 2×1: Data rate up to 10Gbps. Same as USB 3.1 Gen 2.
  • USB 3.2 Gen 2×2: Data rate up to 20Gbps. Uses new dual-lane tech.


USB 4 is based on the Thunderbolt 3 standard, which uses the same connector. USB 4 operates up to 40Gbps, is compatible with Thunderbolt 3, and backward compatible with USB 2.0, USB 3.1, and USB 3.2.

USB Standards & Their Marketing Names

As you can see, USB standards get confusing past USB 3.0. To counter this the USB-IF has suggested marketing names for each standard. Unfortunately, these aren’t often used by online retailers. And with USB 3.2 it doesn’t always distinguish between the old and new standards.

USB SuperSpeed logos

  • USB 1.1 = Low Speed
  • USB 2.0 = High Speed
  • USB 3.0 = SuperSpeed
  • USB 3.1 Gen 1 = SuperSpeed
  • USB 3.1 Gen 2 = SuperSpeed 10Gbps
  • USB 3.2 Gen 1×1 = SuperSpeed
  • USB 3.2 Gen 1×2 = SuperSpeed 10Gbps
  • USB 3.2 Gen 2×1 = SuperSpeed 10Gbps
  • USB 3.2 Gen 2×2 = SuperSpeed 20Gbps

Note how the marketing names don’t allow you to tell the newer USB 3.2 Gen 1×2 from the older USB 3.2 2×1. They also won’t tell you if the device is using Type-C or a legacy connector. On the retail end, a product can list only “USB 3.2” and be legal. But that doesn’t tell you if it supports 5Gbps, 10Gbps, or 20Gbps. You’ll need to read full tech specs to verify you are getting the connection speed desired.

Thunderbolt 3

Thunderbolt is a hardware interface standard created by Intel and Apple. Thunderbolt 3 was released in 2015 and uses USB-C as its connector. Previous versions had used Mini DisplayPort connectors.

Thunderbolt 3 uses its own cables, as they need to support technology not found in other USB-C cables. A Thunderbolt 3 cable may look a lot like a USB-C cable. But their specs are quite different. Thunderbolt 3 cables have some compatibility with USB Type-C ports.

Thunderbolt Logo

There are two types of Thunderbolt 3 cables:

Passive Cables

  • Support 40Gbps data transfer rates up to 0.5 meter in length
  • Support 20Gbps data transfer rates at longer lengths
  • Also supports USB 3.1 Gen 1 (5Gbps)

Active Cables

  • Support 40Gbps data transfer rates at any length
  • Also support USB 2.0 (480Mbps)

Either type of cable will support up to 3A/60W of power. Many can support up to 5A/100W.

USB-C Cables

As USB power and data transfer get complicated, so do their cables. There are different cables with different types of USB connectors on each end. And different cables support a different range of power and data transfer technology. No one type of cable handles every possible connection and technology.

USB-C to USB-C Cables

USB-C to USB-C Cable

USB-C to USB-C Cable

USB-C to USB-C cables is often divided by the USB standard they support. But they are also divided by how much current they can handle. With most cables, you cannot visually identify their specs. You have to pay attention to their technical specs and mark different cables if you have a mixed collection.

USB Power

All USB-C to USB-C cables will charge devices at the same rate, up to 60W. They should all support 3A current. This is sufficient for the majority of USB-C devices. The most common devices to go above 60W are 15-inch laptops.

Some USB-C cables can support up to 5A of current. This allows them to work with 65-100W chargers and devices. Plugging a 3A cable into a 65-100W charger will result in a slower charge for more power-hungry devices. A 5A cable will work fine with chargers and devices operating below 60W. But tends to be more expensive.

USB Standards

All USB-C to USB-C cables should support USB 1.1 and 2.0. Allow for up to 480Mbps data transfer rates. These are the more common and cheapest cables.

USB-C 3.1 Gen and Gen 2 cables are also available. They work with those newer USB standards. And allow for much fast data transfer rates. They are backward compatible with USB 2.0. But they are also more expensive.

Whatever USB standard a USB-C cable supports does not affect its ability to charge a USB-C device. If you only need a cable to charge stick with USB 2.0, as they are cheaper.


USB-C to USB-C cables that offer USB 3.1 or 5A support is required to include an eMarker. It allows a device to verify the cable supports higher data transfer rates and/or current. Think of it as an ID tag, which tells the device exactly what the cable is capable of.

USB-C to USB-C cables that only offer USB 2.0 and 3A support are not required to include an eMarket. And most do not save cost.

Unless the cable has its specs printed on it you cannot visually tell a USB 2.0 cable from a USB 3.1 cable. Or whether it can handle 3A or 5A. If you bought the cable online you can check your order history and look at the specs. Otherwise, you need a USB-C testing device to read the eMarker.

USB-C to USB-A Cables

USB-C to USB-A Cable

USB-C to USB-A Cable

Like USB-C to USB-C cables, USB-C to USB-A cables are divided by the USB standard they support. Unlike C-to-C cables, they all have a 3A current limit.

  • USB-C to USB-A 2.0: Supports up to 480Mbps data transfer rates. Cheapest cable, the best option for just charging.
  • USB-C to USB-A 3.0: Can also be labeled as USB-A 3.1. Allow up to 5Gbps data transfer rates.
  • USB-C to USB-A 3.1 Gen 2: Supports up to 10Gbps data transfer rates. Most expensive cable.

You can charge some USB-C devices with a USB-C to USB-A port. But the power draw is limited by USB-A specifications. Small USB-C devices tend to draw up to 10W. A Quick Charge enabled device and a Quick Charge USB-A port can get up to 18W. They do so by working outside USB-C specifications.

USB-C to Lightning Cables

USB-C to Lightning Cable

USB-C to Lightning Cable

Newer iPhones and iPad Pros support USB Power Delivery. But most of those models use a Lightning port, not USB-C. So Apple made a USB-C to Lightning cable. This allows certain models to connect to a USB-C PD charger and fast charge.

  • iPhone 8
  • iPhone 8 Plus
  • iPhone X
  • iPhone XR
  • iPhone XS
  • iPhone XS Max
  • iPad Pro, 1st Gen
  • iPad Pro, 2nd Gen

Older iPhones can use the cable. But they don’t gain a faster charge from it. The latest iPad Pro (3rd Gen, 2018) has a USB-C port and can use USB-C to USB-C cables.

USB-C is an open standard, but Lightning is owned and controlled by Apple. Apple uses its MFi certification program to verify certain Lightning products work. Newer versions of iOS may warn or even refuse to work with a non-certified product. Until 2019 only Apple made MFi certified USB-C to Lightning cables. Today third-party cables can be MFi certified. They work as well as Apple’s cable and often cost less.

USB-C Adapters

USB-C’s high bandwidth allows it to take the place of several older connectors. On a laptop, USB-C ports can take the place of USB-A, Ethernet, HDMI, and power ports. On phones, it is replacing both the USB port and headphone jack.

This is convenient if all your accessories also use USB-C. But for many of us, it means we need adapters and dongles to make our new device work with our older devices.

USB-C Hubs

A single USB-C port can handle several connections. As such USB-C hubs and docks are also available. These allow several older connections to go through a single Type-C port.

Unfortunately, they don’t always work well. Models without their own power adapter can only handle so much. Some models are tested against only certain model laptops. And not all laptops implement USB-C as well as they should. Some have even been found to cause network interference.

If considering a USB-C hub get one with only the connections you need. And go over reviews, looking for those who have the same model laptop as you.

USB Implementors Forum

USB-IF LogoThe USB Implementers Forum (USB-IF) is a non-profit organization formed by Agere Systems, Apple, HP, Intel, Microsoft, and NEC. It promotes and markets USB. It also maintains USB specifications and a standards compliance program.

They offer USB-IF certification for USB-C products that meet their strict standards. To gain certification a product must pass their USB-IF Compliance Program. And the producing company must be a dues-paying member of the USB-IF.

USB-IF certification is a strong indicator of a good product. But the lack of certification is not a strong indicator of anything. In some cases, certification is forgone to support extra standards. For example, Quick Charge 3.0 is not allowed on a USB-C port under USB-IF standards. But some such devices exist, without any bad reports. Certifications started in late 2017. Products pre-date that often don’t get submitted for certification. Some companies choose not to pay for USB-IF membership, such as RAVPower and Inateck. Others are members but ignore certification, such as Apple and HP.