Names of small numbers

This article lists and discusses the usage and derivation of names of small decimal numbers.

Table of names

The following table lists English language names of small numbers used in the long and short scales, along with the power of 10, engineering notation, and International System of Units (SI) symbols and prefixes.

Power of ten	Engineering notation	Short scale (U.S. and modern British)	Long scale (continental Europe, archaic British, and India)	SI prefix	SI symbol
100	1	One	One
10−1	100×10−3	One Tenth	One Tenth	deci-	d
10−2	10×10−3	One One-Hundredth	One One-Hundredth	centi-	c
10−3	1×10−3	One One-Thousandth	One One-Thousandth	milli-	m
10−6	1×10−6	One One-Millionth	One One-Millionth	micro-	µ
10−9	1×10−9	One One-Billionth	One One-Milliardth	nano-	n
10−12	1×10−12	One One-Trillionth	One One-Billionth	pico-	p
10−15	1×10−15	One One-Quadrillionth	One One-Billiardth	femto-	f
10−18	1×10−18	One One-Quintillionth	One One-Trillionth	atto-	a
10−21	1×10−21	One One-Sextillionth	One One-Trilliardth	zepto-	z
10−24	1×10−24	One One-Septillionth	One One-Quadrillionth	yocto-	y
10−27	1×10−27	One One-Octillionth	One One-Quardilliardth	ronto-	r
10−30	1×10−30	One One-Nonillionth	One One-Quintillionth	quecto-	q
10−33	1×10−33	One One-Decillionth	One One-Quintilliardth	—	—
10−36	1×10−36	One One-Undecillionth	One One-Sextillionth	—	—
0	1×10−∞	0	0
–1
−∞	undefined	Negative Infinity	Negative Infinity

See also

• Names of large numbers
• Number names
• Numeral prefix
• Metric prefix