Pico-

This redirect is about the SI prefix. For other uses, see Pico (disambiguation).

Pico- (symbol p) is a unit prefix in the metric system denoting one trillionth, a factor of 10⁻¹² (0.000000000001).

Derived from the Spanish [pico] Error: {{Lang}}: text has italic markup (help), meaning peak, beak, bit, this was one of the original 12 prefixes defined in 1960 when the International System of Units was established.

The radius of atoms range from 25 picometers (hydrogen) to 260 picometers (caesium). One picolight-year is about nine kilometers (six miles).

Metric prefixes in everyday use

Prefix	Symbol	Factor	Power
tera	T	1000000000000	1012
giga	G	1000000000	109
mega	M	1000000	106
kilo	k	1000	103
hecto	h	100	102
deca	da	10	101
(none)	(none)	1	100
deci	d	0.1	10−1
centi	c	0.01	10−2
milli	m	0.001	10−3
micro	μ	0.000001	10−6
nano	n	0.000000001	10−9
pico	p	0.000000000001	10−12