File Sizes and Transfer Speeds

Author: Swapna Naraharisetty, 2BrightSparks Pte. Ltd.

The size of a file is the amount of data stored in a file, or the measure of space consumed by a file on a storage medium such as an internal / external drive, network drive, FTP server or cloud. File sizes are measured in Bytes (B), Kilobytes (KB), Megabytes (MB), Gigabytes (GB), Terabytes (TB) and so on. The file sizes can be measured using a binary system (where kilo means 1024) or metric system (kilo means 1000).

Data transfer speed is a measure of data that is transferred from one location to another in a given amount of time. Data transfer speeds are measured in bits per second (b) or bytes per second (B). A bit is represented with a lowercase “b”, while a byte is represented with an uppercase “B”, for example: Kbps means ‘Kilobits per second’, and KBps means ‘Kilobytes per second’.

Case matters - but the following brief explanation should give you all the information you need to answer the question: "How big is my file really?!"

What Is a File Size?

File size is the measurement of digital storage occupied by a file and is typically expressed in bytes (B), kilobytes (KB), megabytes (MB), gigabytes (GB), or terabytes (TB). The bigger the file, the larger the amount of data it holds, and the longer it takes to transfer or back up. A few common examples are documents (usually a few KB), photos (usually a few MB), videos (hundreds of MB and more), and software or disk images (usually several GB in size).

What Is a Large File Size?

A "large" file size is relative, but in general, any file over 100MB can be large for email or cloud transfers. For backup and storage, files over 1GB are typically large. Some examples are high-definition video, raw sets of photos, virtual machine images, and complete database dumps. Large files transfer more slowly and are more likely to bust storage limits or invoke throttling on cloud services.

When backing up large files, tools like SyncBackPro can help by offering features such as compression, multi-threaded transfers, and delta copying to improve performance and reduce bandwidth usage.

File Sizes

Bit

A bit is the smallest unit of data, which holds either 1 or 0 (or on/off). The unit of a bit is represented by a lowercase b.

Byte

A byte is a sequence of 8 bits. A byte can represent a letter, a number or a symbol. The unit of a byte is represented by an uppercase B.

Kilobyte

A kilobyte is equal to 1024 bytes. It is normally used to describe the size of small files stored on a storage device e.g. text files. The Kilobyte is abbreviated as KB.

Megabyte

A Megabyte is 1024 kilobytes. It is used to measure the size of large files e.g. image files or JPEG files. The Megabyte is abbreviated as MB.

Gigabyte

A Gigabyte is 1024 megabytes. It is used to measure the volume of storage devices. The Gigabyte is abbreviated as GB.

Terabyte

A Terabyte is 1024 gigabytes. It is used to measure the capacity of large storage devices. The Terabyte is abbreviated as TB.

Transfer Speeds

bps

means one bit per second. Note the small b to indicate bits and not bytes.

Bps

means one byte per second or 8 bits per second. Note the capital B to indicate bytes and not bits.

kBps

means one kilobyte per second or 1000 bytes per second. This uses a decimal prefix.

KiBps

means one kibibyte per second or 1024 bytes per second. This uses a binary prefix (note the i).

MBps

means 1,000,000 bytes per second. This uses a decimal prefix.

MiBps

means one mebibyte per second or 1,048,576 bytes per second. This uses a binary prefix.

GBps

means 1,000,000,000 bytes per second. This uses a decimal prefix.

GiBps

means one gibibyte per second or 1,073,741,824 bytes per second. This uses a binary prefix.

TBps

means 1,000,000,000,000 bytes per second. This uses a decimal prefix.

TiBps

means one tebibyte per second or 1,099,511,627,776 bytes per second. This uses a binary prefix.

SyncBack

In SyncBack the file sizes and transfer speeds are expressed in bytes, kilobytes, megabytes and so on, and not in bits form.

After V8.5.43.0, SyncBack correctly uses the binary prefix for transfer speeds. SyncBack V8.5.43.0 and earlier show transfer speeds using the decimal prefix, but they are actually binary values. For example, 1MBps is shown but it is actually 1,048,576 bytes per second and not 1,000,000 bytes per second.

SyncBack uses the binary system (like Windows) to describe file sizes, and not the metric system (SI). It is also shown the same way as in Windows. For example, a file that is 3,145,728 bytes in size is shown as being 3MB. Technically, it should be shown as 3MiB, but to be consistent with Windows it is displayed as 3MB. Windows uses the JEDEC 100B.01 standard.