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

How to use this tool

Enter your number. Type a complete finite decimal, E-notation value such as 1.5e3, or a × 10^b expression.
Set significant figures. Enter a whole number from 1 to 20 to control rounding precision.
Copy a normalized form. Each result is normalized after rounding, so scientific and engineering mantissas stay in their required ranges.

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.

Rounding and normalization

The converter rounds to the selected whole-number count of significant figures before it formats a result. It then normalizes the exponent again. For example, rounding 9.999 to three significant figures produces 1.00 × 10^1, not 10.00 × 10^0, because a scientific-notation mantissa must remain at least 1 and less than 10 in absolute value.

Engineering notation uses the same post-rounding check, with an exponent divisible by three and a nonzero mantissa from 1 up to (but not including) 1000. The input must be one complete finite number, in decimal, E notation, or a × 10^b form; the significant-figure setting must be an integer from 1 to 20.

Frequently asked questions

What is scientific notation?

Scientific notation writes a nonzero number as a × 10^b, where 1 ≤ |a| < 10 and b is an integer. For example, 12,345 is 1.2345 × 10^4.

What is engineering notation?

Engineering notation uses an exponent that is a multiple of 3, so its mantissa is at least 1 and less than 1000. This aligns with SI prefixes such as kilo, mega, milli, and micro.

What happens when rounding changes the exponent?

The converter rounds first, then renormalizes the result. For example, 9.999 to three significant figures becomes 1.00 × 10^1, not 10.00 × 10^0.

What inputs are accepted?

Enter a complete finite decimal, E-notation value, or a × 10^b expression. Significant figures must be a whole number from 1 to 20.