Not all USB speeds are created equal (and sure, the numbers complicate issues)

Abstract

There’s quite a lot of USB codecs on the market, using completely different connectors, knowledge charges, and charging speeds. You’ll want to match like equipment to get essentially the most out of your units.
The most important cut up is between USB-A and USB-C connectors, the latter normally enabling quicker knowledge and energy, although not all the time. Verify specs earlier than shopping for something.
One of the best USB format is USB 4 2.0, which peaks at 120Gbps and helps Thunderbolt 5. It is exceptionally uncommon, so you will most likely be wonderful with the bottom 40Gbps USB 4 spec.

The U in USB is meant to face for Common, but you would be forgiven for considering it was something however. Past utilizing completely different connector sorts, some USB codecs provide wildly completely different knowledge and charging speeds. Often, connections might even assist charging however not knowledge, or vice versa. You have encountered that dilemma if you happen to’ve tried to make use of wired CarPlay or Android Autoand did not plug into the only port marked for knowledge sync.

In case you’re having hassle sorting issues out, this information is supposed to be a fast and useful primer — I am not going to enter extreme depth about every model of USB. In actual fact, the one main division you (normally) want to fret about is USB-A versus USB-C, except maybe you are a video editor or connecting an exterior graphics card. That’ll make extra sense in just a few moments.

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USB 1.0/1.1

The start of the expertise

USB Implementers Discussion board / Pocket-lint

The unique model of USB dates again to 1996, and was restricted to a whopping 1.5 megabits per second (Mbps) of knowledge and 0.5W of energy supply. Extra importantly, it launched the oblong USB-A (AKA Sort-A) connector sort, which remains to be in use in the present day.

You’ll be able to, in principle, plug a USB 1.0 peripheral into a contemporary laptop computer with none points.

Realistically, the oldest model of USB you are more likely to encounter is 1.1. That upgraded knowledge to 12Mbps, and energy to 2.5W, enough to attach mice and keyboards. You would not need to cost a state-of-the-art smartphone utilizing this tech — it’d take over 5 and a half hours to fully replenish an iPhone 16 Pro.

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USB 2.0

The usual that refuses to die

A USB stick on an old wooden storage box.

That is the oldest format nonetheless in lively use. Whereas its energy supply is capped at 2.5W in most circumstances, knowledge speeds rise to 480Mbps. That is much more affordable for exterior storage drives, or syncing cellular units, although file sizes have grown a lot over time that it most likely will not really feel prefer it. Actually, you need to keep away from utilizing USB 2.0 to again up a contemporary laptop — it will take over 9 hours to repeat a 2TB drive.

It is price noting that Apple nonetheless caps knowledge at 2.0 speeds typically, even when it is utilizing extra fashionable connector sorts.

Most USB 2.0 units depend on a USB-A connector, however a number of connector sorts blossomed out of the usual, together with Sort-B, Mini-A, Mini-B, Micro-A, and Micro-B. Though the primary three have fallen by the wayside, you would possibly nonetheless run into micro-USB ports in uncommon circumstances.

It is price noting that Apple nonetheless caps knowledge at 2.0 speeds typically, even when it is utilizing extra fashionable connector sorts. Particularly, I am considering of Lightning cables, and the USB-C ports on non-Professional iPhones. The Lightning format has been fully abolished from Apple’s latest merchandise as of 2025.

Five Lightning port cables in a row in different colors.

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USB 3.0

The brand new baseline, and a brand new connector

A red USB-C cable on an old cedar chest.

3.0 has largely supplanted 2.0 because the minimal commonplace, boosting energy to at the least 4.5W, and knowledge speeds of as much as 5 gigabits per second (Gbps). 5Gbps transfers could make an enormous distinction — that very same 2TB backup I discussed earlier would end in beneath an hour.

Virtually as important because the pace enhance is widespread assist for USB-C (AKA Sort-C). When you’ll nonetheless see 3.0 gear with USB-A connectors, USB-C is more and more de facto, each due to newer requirements and due to comfort. USB-C is reversible, which means there is no fear a few cable failing to insert correctly. Many individuals complain that USB-A cables all the time appear to enter upside-down in your first strive.

A white iPhone 16e getting charged over USB-C on a red gradient background.

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USB 3.1 and three.2

Ditching the separate energy cables

The most important factor in USB 3.1 is widespread assist for USB Energy Supply (a.ok.a. USB-PD). This unlocks much more juice than earlier codecs, at the least as much as 100W. That is sufficient to energy many laptops, and absolutely recharge telephones in lower than an hour, although PD is finally held again by the capability of your system, cable, and/or adapter setup. A 100W cable will not max out if you happen to’re utilizing a 30W adapter, for instance.

USB 3.1 Gen 1 gives knowledge speeds of as much as 5Gbps, whereas Gen 2 doubles issues to 10Gbps. Confusingly, USB 3.2 Gen 1×1 and Gen 2×1 have the identical cut up — you must bounce to Gen 2×2 to attain 20Gbps.

Merchandise with USB-PD 3.1 assist energy of as much as 240W, sufficient for some gaming laptops. I ought to add that in some circumstances, USB-PD 3.1 could be paired with USB 3.0 and even 2.0 knowledge speeds — however since USB-PD 3.1 launched in 2021, you will normally see it related to USB 3.1 or later.

All variations of USB-PD require USB-C.

A pair of gaming laptops, one showing Xbox PC Game Pass.

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USB 4 and 4 2.0

One of the best you may get for now

A Thunderbolt 5 cable. — Newswire / Pocket-lint

Newswire / Pocket-lint

This is not as widespread correctly, however adoption is rising, and at this stage I would not purchase a brand new PC or Mac with out at the least one USB 4 connection. Sometimes, the usual helps transfers as much as 40Gbps, which is nearly a should if you happen to’re doing 4K video enhancing. Returning to that 2TB backup instance, a USB 4 configuration would possibly full the method in lower than seven minutes. USB-PD is assumed right here.

USB 4 contains Thunderbolt compatibility by default.

Even higher, USB 4 contains Thunderbolt compatibility by default. That is an ordinary utilized by various high-speed equipment, although most incessantly you are going to encounter Thunderbolt docks, which broaden port choices with minimal congestion. {Hardware} makers are likely to at the least provide Thunderbolt 4, which absolutely exploits that 40Gbps capability. It is sufficient bandwidth to deal with two 4K60 DisplayPort screens concurrently.

On the chopping fringe of the trade is USB 4 2.0 (AKA USB 4 v2). Usually, this peaks at 80Gbps, however it may obtain 120Gbps if knowledge in a single path is restricted to 40Gbps. It is also required to squeeze essentially the most out of Thunderbolt 5.