What is scientific notation?

Scientific notation expresses a number as a product of a mantissa (a × 10^b) where 1 ≤ |a| < 10 and b is an integer. For example, 12,345 becomes 1.2345 × 10^4. It is used in science and engineering to compactly express very large or very small numbers.

What is engineering notation?

Engineering notation is similar to scientific notation, but restricts the exponent to multiples of 3 (matching the SI prefix scale: kilo-, mega-, giga-, milli-, micro-, nano-). So 12,345 becomes 12.345 × 10^3 rather than 1.2345 × 10^4.

E-notation is shorthand for scientific notation used in programming and calculators: "1.2345E4" means 1.2345 × 10^4. Most programming languages accept this format directly.

What are significant figures?

Significant figures (or significant digits) are the meaningful digits in a number that carry information about its precision. Leading zeros are not significant; trailing zeros after a decimal point are. Setting significant figures in the converter rounds the mantissa to that precision.

Scientific Notation Converter - Standard, Scientific, Engineering & E-Notation

Scientific notation

Scientific notation expresses any real number as a × 10^b, where 1 ≤ |a| < 10 and b is an integer. This compact form makes it easy to compare very large numbers (like the distance to the Sun: 1.496 × 10^11 m) or very small numbers (like the size of an atom: 1 × 10^−10 m).

Engineering notation

Engineering notation is a variant where the exponent is always a multiple of 3, matching the SI prefix scale: 10^3 (kilo), 10^6 (mega), 10^9 (giga), 10^−3 (milli), 10^−6 (micro), 10^−9 (nano). This makes it natural to read off units: 12.345 kΩ instead of 1.2345 × 10^4 Ω.

Significant figures

The number of significant figures reflects the precision of a measurement. When converting between forms, trailing zeros in the mantissa carry meaning: 1.20 × 10^3 indicates three significant figures, while 1.2 × 10^3 indicates only two.

SI prefix reference

Prefix	Symbol	Value	Example
Yotta	Y	10²⁴	~8.5 YB (internet traffic per year)
Zetta	Z	10²¹	~120 ZB (global data by 2023)
Exa	E	10¹⁸	1 EB = 1 billion GB
Peta	P	10¹⁵	~5 PB (words ever spoken by humans)
Tera	T	10¹²	1 TB hard drive
Giga	G	10⁹	1 GHz processor clock
Mega	M	10⁶	1 MW wind turbine output
Kilo	k	10³	1 km = 1,000 m
Hecto	h	10²	1 hPa (atmospheric pressure)
Deca	da	10¹	1 dam = 10 m
Deci	d	10⁻¹	1 dL = 0.1 L
Centi	c	10⁻²	1 cm = 0.01 m
Milli	m	10⁻³	1 mA (LED current)
Micro	μ	10⁻⁶	1 μF capacitor
Nano	n	10⁻⁹	7 nm chip process
Pico	p	10⁻¹²	1 pF (parasitic capacitance)
Femto	f	10⁻¹⁵	1 fm = proton diameter scale
Atto	a	10⁻¹⁸	1 as (attosecond laser pulse)
Zepto	z	10⁻²¹	1 zg (single molecule mass)
Yocto	y	10⁻²⁴	~1.67 yg = 1 atomic mass unit

Worked conversion examples

Converting 0.00000045 between notation forms:

Standard form: 0.00000045
Scientific notation: 4.5 × 10⁻⁷
Engineering notation: 450 × 10⁻⁹ = 450 nanofarads (450 nF) - the exponent is adjusted to the nearest multiple of 3, and the SI prefix "nano" (n) replaces × 10⁻⁹.

Converting 12,500,000:

Scientific notation: 1.25 × 10⁷
Engineering notation: 12.5 × 10⁶ = 12.5 MHz (megahertz) if this is a frequency.