---
title: "USB 3.x size — 5, 10 or 20 Gbit/s depending on generation"
description: "USB 3.x: 5 Gbit/s originally, renamed repeatedly — check the speed, not the name. Full dimensions in millimetres, centimetres and inches, and what the standard actua"
url: https://atoneplace.net/size/usb-3/
site: "At One Place"
---

# USB 3.x size

**USB 3.x: 5, 10 or 20 Gbit/s depending on generation**

This is the family where the naming became genuinely misleading. USB 3.0 (5 Gbit/s) was renamed USB 3.1 Gen 1, then USB 3.2 Gen 1, without the hardware changing at all. 10 Gbit/s is Gen 2, and 20 Gbit/s is Gen 2×2. A device advertised as "USB 3.2" may be any of the three. The USB-IF now recommends marketing by speed — "USB 5Gbps", "USB 10Gbps" — precisely because the version numbers stopped carrying information.

## The numbers

- **Specification:** 5, 10 or 20 Gbit/s depending on generation
- **Defined by:** USB-IF

> The same physical port and cable can be any of these speeds. Version numbers alone do not tell you which.

## USB

| Size | Millimetres | Inches |
| --- | --- | --- |
| USB-C connector | 8.34 × 2.56 mm | 0.33 × 0.10 |
| USB 3.x ← | 5, 10 or 20 Gbit/s depending on generation | — |
| USB 2.0 | 480 Mbit/s, 2.5 W (500 mA at 5 V) | — |
| USB4 | 20, 40 or 80 Gbit/s; USB-C connector only | — |

## Common questions

### What size is USB 3.x?

5 Gbit/s originally, renamed repeatedly — check the speed, not the name.

### Which standard defines USB 3.x?

USB-IF

## Related pages

- [USB-C connector size](https://atoneplace.net/size/usb-c/)
- [USB 2.0 size](https://atoneplace.net/size/usb-2/)
- [USB4 size](https://atoneplace.net/size/usb-4/)

## Sources

- Official vendor product documentation — At One Place (/about/)