Data transfer rate | CMD (2024)

Quick links

• What’s a data transfer rate?
• How do I calculate a data transfer rate?
• How do I test a data transfer rate?
• How do I increase my data transfer rate?
• How do data transfer rates compare?
• What’s the data transfer rate of a typical hard drive?
• What’s the data transfer rate of a Cat6 cable?
• What’s the data transfer rate of a USB flash drive?
• USB vs Micro-SD—which has the better data transfer rate?
• How long does it take to transfer data to or from a phone by USB?

What’s a data transfer rate?

A data transfer rate tells you how much digital data will travel from one place to another—from a hard drive to a USB flash drive, for example—in a specific period of time.

Rather confusingly, you’ll see it measured in:

• bits per second
• bytes per second

The difference between bits and bytes is explained below.

However, with today’s technology being capable of transferring large amounts of data at fast speeds, you’re more likely to see it measured in megabits per second (Mbps) or megabytes per second (MBps). (A megabit is around a million bits. A megabyte is roughly a million bytes.)

Sometimes—when downloading a file from the internet, for instance—you might see the data transfer rate measured in kilobytes per second (KBps).

Most internet service providers use the Mbps figure when advertising the speed of their broadband/fibre products.

Bits vs bytes—what they mean

A byte is the bigger unit—there are eight bits in every byte.

How do I calculate a data transfer rate?

There’s a simple way to work this out, using the file size (bytes) and the transfer speed (bits).

It’s easier if you know the megabits per second figure in megabytes (MB). Remember, there are eight bits in every byte, so convert the transfer speed into megabytes per second (MBps) by dividing it by 8:

• 100Mbps ÷ 8 = 5MBps

You now know that, at maximum, 12.5MB of the file will transfer every second.

As the file is 250MB in size, calculate its transfer rate by dividing 250 by 12.5:

• 250MB ÷ 12.5 MBps = 20 seconds

It will take 20 seconds to transfer a 250MB file across a 100Mbps connection.

This is only a rough estimate, however, and there are several other factors that come into play.

How do I test a data transfer rate?

There are lots of online tools that let you test data transfer rates. Most are called ‘internet speed tests’ or something similar, as they work by testing the speed of your internet connection.

People generally use these tools to make sure they are getting the broadband speeds their internet providers have promised them.

More sophisticated tools are available that can also test how efficiently your hardware is performing. These are typically software programs you download and then run.

The simple speed tests work by simulating a download and an upload of a data file and measuring the results. They assess the:

• download speed—how quickly a file transfers from the internet to your computer or home network
• upload speed—how quickly you can upload a file to the internet from your computer or home network
• latency (known as ping)— whether there’s any delay in how long it takes data to travel from a server to your computer

Some popular tools include the following:

Online speed tests

• http://www.broadbandperformance.co.uk/
• https://www.speedtest.net/
• https://www.thinkbroadband.com/speedtest

Speed and hardware testing software

• CrystalDiskMark
• HDTach
• ATTO Disk Benchmark
• LAN Speed Test

How do I increase my data transfer rate?

Often, a slow data transfer rate is due to your computer’s hard drive. Fortunately there are ways to speed up your drive and get it performing more quickly, including:

• changing the file system used to format your drive from FAT32 to NTFS
• tweaking the system settings for better performance
• turning off disk compression

These may sound complicated but implementing them is actually quite simple—you don’t need to be an IT expert! Just follow the step-by-step guides at MakeUseOf and Techwalla.

Another method is to upgrade from USB 2.0 to USB 3.0 (or higher)—the newest versions of USB are designed to transfer data at much quicker speeds.

Read more about USB data transfers here and about USB versions here.

How do data transfer rates compare?

It’s not always clear how to get the fastest data transfer rates. What version of USB do you need? What type of hardware? Are certain cables and connectors faster than others?

The tables below show data transfer rates for different:

• versions of USB
• types of connection (e.g. USB, Thunderbolt, Ethernet and so on)
• types of media (e.g. MP3s, YouTube videos, films and so on)

USB—comparison of data transfer rates

Click here for an explanation of USB versions

Types of connection—comparison of data transfer rates

Types of media—comparison of data transfer rates

What’s the data transfer rate of a typical hard drive?

Because of how hard drives work—with rotating discs—and the way in which they store and access data, they are usually limited to a transfer rate of about 100 MBps–200 MBps.

The data transfer rate of a hard drive depends on the model and the interface it uses to function (usually SATA). However, it’s also a combination of two different types of transfer rate—the external transfer rate and the internal transfer rate.

• External transfer rate (also called burst data transfer rate or interface transfer rate)—the speed at which data passes between the system memory and the internal buffer or cache built into the drive
• Internal transfer rate (also called maximum or minimum sustained transfer rate)—the speed at which data is read and written to the hard disk

The external transfer rate is usually faster than the internal rate because it’s purely electronic, and doesn’t rely on how efficiently actual physical components (the disk platters inside the drive) operate.

What’s the data transfer rate of a Cat6 cable?

A Cat6 (Category 6) cable is the type of cable you’d use to transfer data over an Ethernet connection or network.

These cables are designed and made to transmit data reliably at high speeds and across a bigger range of frequencies. However, the data transfer rate does depend on the type of Ethernet connection.

For example, if you wanted to download a 4.5GB DVD:

• on an Ethernet connection (10 Mbps), it would take one hour
• on a Fast Ethernet connection (100 Mbps), it would take six minutes
• on a Gigabit Ethernet connection (1Gbps), it would take 36 seconds
• on a 10 Gigabit Ethernet connection (10Gbps), it would take 3.6 seconds

The Cat6 cable is the latest in a series of cables—Cat3, Cat4, Cat5—used for transmitting data via Ethernet. It’s the only Cat cable that supports the high speeds the 10Gigabit Ethernet connection is capable of achieving.

What’s the data transfer rate of a USB flash drive?

This depends on which USB version the flash drive supports. The most recent versions of USB—3.0 and higher—deliver maximum transfer speeds of 5Gbps (640 MBps) and above.

However, the specifications that the manufacturers of most of these USB drives provide warn that you’re unlikely to ever achieve the maximum possible speeds. With that in mind, you can expect transfer rates of 800 Mbps (100MBps) or less, for USB 3.0.

This is generally because USB versions are developed for future technology rather than what we have at present, which isn’t capable of exploiting those versions’ full potential.

USB vs Micro-SD—which has the better data transfer rate?

Comparing USB and Micro-SD is tricky in that you’re not really comparing like for like.

With USB 3.0, you get a read speed of 100 MBps, but much lower write speeds. With USB 3.1, you get read and write speeds of up to 400 MBps, and most new computers come with this capability.

Micro-SD memory cards, on the other hand, are each designated a speed class according to their minimum write speed. This write speed tells you what resolution of photo or video the device—a digital camera, video recorder or smartphone—is capable of recording (e.g. HD, 4K etc.).

The table below shows some of the different designations and speeds:

Read more about SD speed classes at the SD Association’s website.

USB speeds are affected by how many devices are sharing one port. On many laptops, the USB ports are all routed through a single internal hub—if all the ports are being used, speeds will be slower.

A Micro-SD card in a digital camera or a smartphone is always going to be faster in the device than when it’s connected to a PC via a USB reader.

How long does it take to transfer data to or from a phone by USB?

Again, this depends on the version of USB. The table above shows the maximum transfer rates for each version available up to now. The quality of the cable used will also be a factor.

Related content

USB data transfer guide

Does USB 3.0 work with USB 2.0?—A guide to USB versions and compatibility

Identifying your USB connector or USB cable type