What Is TB in Computers?

By Lynette Arceneaux

Your external hard drive might hold TBs of information.
i external storage image by Albert Lozano from Fotolia.com

Unfamiliar computer acronyms and jargon can sometimes feel like a foreign language. One computer term that might have people scratching their heads is "TB," which refers to the amount of information in terabytes that a computer can store.


A bit is the smallest increment of data on a computer. Bits are usually assembled into groups of eight to create a byte. Computer memory and storage space are often measured in megabytes (MB), gigabytes (GB) and terabytes (TB).


One terabyte is about a trillion bytes or 1,000 gigabytes. A TB can hold approximately 500 million typewritten pages, 25 million songs or 300 feature-length films.


Manufacturers of hard drives often use the decimal system, defining 10GB of storage space as 10 billion bytes. Your computer, however, uses a binary system, defining 10GB as 10,737,418,240 bytes. Therefore, you might notice that your computer recognizes 10GB as capable of storing only 9.31GB: the result of a difference in definition, not a computer error.

Fun Fact

The "tera" in terabyte stems from the Greek word for monster. This is confirmed by the Oxford English Dictionary, which explains that the prefix "tera-" is affixed to the names of units to create the names of units 10 to the 12th power times larger--or one million million times larger. The OED cites such examples as terahertz, terawatt and terasecond.