Tera-

This redirect is about the SI prefix. For other uses, see Tera.

Tera is a unit prefix in the metric system denoting multiplication by 10¹² or 1000000000000 (one trillion short scale; one billion long scale). It has the symbol T. Tera is derived from the Greek word τέρας teras, meaning "monster". The unit prefix was confirmed for use in the International System of Units (SI) in 1960.

Examples of its use:

• terahertz radiation: electromagnetic waves within the band of frequencies from 0.3 to 3 THz. Visible light is around 500 THz.
• terabit and terabyte, units used in data storage. Tebi-, or 2⁴⁰ is the closest binary prefix being ~9.95% greater than 10¹².
• teragram: equal to 10⁹ kg. The Great Pyramid of Giza has a mass of about 6 Tg.
• terasecond: approximately 31,558 years
• teralitre: equal to 10⁹ m³. Lake Zurich contains about 4 TL of water.
• terawatt: used to measure total human energy consumption. In 2010 it was 16 TW (TJ/s).
• terametre (= 1,000,000,000 km): Light travels 1.079 Tm in one hour.

SI prefixes

Prefix		Base 10	Decimal	Adoption
Name	Symbol
quetta	Q	1030	1000000000000000000000000000000	2022
ronna	R	1027	1000000000000000000000000000
yotta	Y	1024	1000000000000000000000000	1991
zetta	Z	1021	1000000000000000000000
exa	E	1018	1000000000000000000	1975
peta	P	1015	1000000000000000
tera	T	1012	1000000000000	1960
giga	G	109	1000000000
mega	M	106	1000000	1873
kilo	k	103	1000	1795
hecto	h	102	100
deca	da	101	10
—	—	100	1	—
deci	d	10−1	0.1	1795
centi	c	10−2	0.01
milli	m	10−3	0.001
micro	μ	10−6	0.000001	1873
nano	n	10−9	0.000000001	1960
pico	p	10−12	0.000000000001
femto	f	10−15	0.000000000000001	1964
atto	a	10−18	0.000000000000000001
zepto	z	10−21	0.000000000000000000001	1991
yocto	y	10−24	0.000000000000000000000001
ronto	r	10−27	0.000000000000000000000000001	2022
quecto	q	10−30	0.000000000000000000000000000001
Notes

See also

• RKM code