Micro-USB: The Older Small USB Connector
Where does it come from?
Wikipedia says the USB-IF announced the Micro-USB connectors on 4 January 2007 as a thinner successor to Mini-USB, about half the thickness, so they would fit into thinner portable devices. The USB-IF’s USB 2.0 specification page lists the Micro-USB Cables and Connectors Specification, Revision 1.01, published on 4 April 2007, with follow-up engineering change notices dated from December 2008 to March 2010 covering details such as ID pin resistance, the chamfer on the connector and the maximum unmating force.
What does the plug look like?
Wikipedia describes a trapezoid-shaped plug measuring about 6.85 mm by 1.80 mm, with five contact pins, one more than the standard full-size USB plug. One long edge is angled, which is why it only goes in one way. Compare that with USB-C, a symmetrical oval that fits either way up.
| Micro-USB | USB-C | |
|---|---|---|
| Plug shape | Trapezoid, one way up | Symmetrical oval, either way up |
| Size | About 6.85 by 1.80 mm | About 8.34 by 2.56 mm |
| Rated insertion cycles (Wikipedia) | 10,000 | 10,000 |
| Typical phone data speed | USB 2.0, 480 Mbit/s | USB 2.0 or faster, depending on the phone |
Versions you might meet
- Micro-B: the plug on a typical phone cable.
- Micro-B SuperSpeed: a wider plug for USB 3.0. Wikipedia says a SuperSpeed socket accepts the older plug, but an older socket cannot accept the wider plug.
- Micro-AB and USB On-The-Go: Wikipedia says a Micro-AB socket accepts either a Micro-A or Micro-B plug, so a device can act as a host or as a peripheral depending on the plug it sees. This is how some phones could read a USB drive through an adapter.
How fast is it?
Micro-USB supports the same speeds as the USB version behind it. Wikipedia lists 12 Mbit/s for the original full speed, 480 Mbit/s for USB 2.0 and 5 Gbit/s for the SuperSpeed variant. Nearly all phones used the USB 2.0 type, so a Micro-USB phone moves files at no more than 480 Mbit/s. See USB 2.0 vs USB 3.x for what that means in practice.
The common charger idea
Micro-USB was the connector behind the first “one charger for every phone” agreements. Wikipedia lists the milestones: the OMTP group endorsed Micro-USB in September 2007, the GSM Association followed in February 2009, and the ITU adopted it as a “Universal Charging Solution” in October 2009. The European Union also organised a voluntary agreement in 2009 for a common external power supply. That voluntary approach was replaced by law: the Irish government’s notice says USB-C is required on phones, tablets and similar devices sold in the EU from 28 December 2024.
Why did phones move on?
The USB-IF’s USB Type-C page says newer platforms were reaching a point where existing USB plugs and receptacles were inhibiting innovation. Type-C was created for slimmer devices and adds reversible plug orientation, along with scalable power and performance. In practice, it also fixed the daily annoyance of finding the right way to plug in a Micro-USB cable in the dark.
I still have a Micro-USB phone. What now?
- Keep using the right cable. The phone needs a Micro-USB cable. A USB-C cable will not fit it.
- Buy a certified cable. Cheap, unmarked cables are the same risk on any connector. See cable buying safety.
- Check the charger separately. Charging speed on older phones depends on the phone’s own limit, so a bigger charger will not make it faster. The charger hub explains the wattage numbers.
- Plan the upgrade. If you are buying a new phone, expect USB-C or, on older iPhones, Lightning.
Do I need this page?
Our launch library focuses on current phones, so no phone page links here yet. We keep this explainer for anyone with an older device, and so that pages for older phones can link to it later.
Related
USB-C vs Lightning, USB 2.0 vs USB 3.x, cable buying safety, all cables.