Multiples of bits  

SI decimal prefixes  IEC binary prefixes  
Name (Symbol) 
Standard SI 
Binary usage 
Name (Symbol) 
Value 
kilobit (kbit)  10^{3}  2^{10}  kibibit (Kibit)  2^{10} 
megabit (Mbit)  10^{6}  2^{20}  mebibit (Mibit)  2^{20} 
gigabit (Gbit)  10^{9}  2^{30}  gibibit (Gibit)  2^{30} 
terabit (Tbit)  10^{12}  2^{40}  tebibit (Tibit)  2^{40} 
petabit (Pbit)  10^{15}  2^{50}  pebibit (Pibit)  2^{50} 
exabit (Ebit)  10^{18}  2^{60}  exbibit (Eibit)  2^{60} 
zettabit (Zbit)  10^{21}  2^{70}  zebibit (Zibit)  2^{70} 
yottabit (Ybit)  10^{24}  2^{80}  yobibit (Yibit)  2^{80} 
See also: Nibble · Byte · Multiples of bytes Orders of magnitude of data 
A terabit is a unit of information or computer storage, abbreviated Tbit (or Tb).
1 terabit = 10^{12} bits = 1,000,000,000,000 bits (one trillion, or, using the long scale, one billion). 1 terabit is equal to 1,000 (decimal) gigabits and a tebibit to 1,024 (binary) gibibits. 1 terabit is also equal to 125 gigabytes.
The terabit is closely related to the tebibit, which is equal to 2^{40} or 1,099,511,627,776 bits. Note that the difference between a trillion bits and a tebibit is about 10%.But in normal computer parlance a terabit would really refer to a tebibit of 10^{40}
