Bytes per Second

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bytes per second BpsBytes per second (Bps) is a typical way of measuring file transfer speeds. In most cases it is expressed in kilobytes per second (kBps) or megabytes per second (MBps). It can be confusing because ISP’s often state their Internet access speed in megabits per second. Bits and bytes, commonly used interchangeably, are not the same. A byte corresponds to eight bits.

The terms can be unclear because storage device sizes are given in Megabytes or Gigabytes. For example a two hour HD movie is about 3.0-4.5 Gigabytes (GB), or about 3000-4500 Megabytes (MB). When you go to download that movie to your computer or mobile device, the time it will take depends on your connection speed in Megabits. So a 3 GB HD movie will take 54 minutes to download at 5 Megabits per second.

To further confuse the issue, some transfer rates for storage devices are given in bytes per second (Bps), and others are in bits per second (bps). For example USB 3.0 has a maximum transfer speed of 4.8 Gbps (Gigabits per second). An eSATA external hard drive speed is about 3.2 Gbps. But you’ll find internal hard drives transfer speeds listed in terms of megabytes per second (MBps). In addition, when copying files to a USB or external hard drive, your operating system will probably show a progress bar in bytes per second, even though the specifications of the device will be in bits per second. It’s no wonder then, when the terms are often misquoted or misapplied.

Always be sure whether you’re talking about bits or bytes, especially when it comes to transfer speeds, your Internet connection, and the performance you can expect when streaming online.

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