Scientific Notation & Significant Figures
Convert between standard, scientific, engineering and E-notation, round to significant figures, and count sig figs digit by digit.
Enter a number
Accepts plain numbers, E-notation (6.022e23) and a × 10^b forms.
Result
About this tool
Scientific notation writes a number as a coefficient times a power of ten, which makes very large and very small values easy to read and compare. This tool converts any number between standard form, scientific notation (1 ≤ |a| < 10), engineering notation (exponent in multiples of three) and E-notation, rounds to any number of significant figures, and explains digit by digit how many significant figures a number has. All math runs in your browser using exact string arithmetic, so no precision is lost even with extreme magnitudes.
How to use
- 1 Choose a mode: Convert, Round, or Count significant figures.
- 2 Type a number — plain (123456), E-notation (6.022e23) or a × 10^b are all accepted.
- 3 Read the results: every notation, the rounded value, or the digit-by-digit sig-fig breakdown.
- 4 Tap the copy button to copy any result, or use the example chips to explore.
How it works
The tool parses your input into a sign, a string of significant digits and a power of ten, all as text to avoid floating-point error. Scientific notation places the decimal point after the first digit; engineering notation shifts the exponent to the nearest lower multiple of three so units like kilo, mega and micro line up. Rounding to significant figures keeps the leading digits, inspects the first dropped digit, and rounds half away from zero, carrying over (e.g. 999 → 1000) when needed. Significant-figure counting follows the standard rules: leading zeros never count, zeros between significant digits do, and trailing zeros count only when a decimal point or explicit exponent is present.
Frequently asked questions
What is the difference between scientific and engineering notation?
Scientific notation uses any exponent with a coefficient between 1 and 10, e.g. 4.7 × 10⁴. Engineering notation restricts the exponent to multiples of three (…, 10³, 10⁶, 10⁹), giving 47 × 10³, which lines up directly with SI prefixes such as kilo, mega and giga.
How are trailing zeros handled in significant figures?
Trailing zeros are significant only when there is a decimal point (100.0 has four sig figs) or an explicit exponent. In a bare integer such as 1200 they are ambiguous and conventionally treated as not significant — write 1.2 × 10³ or 1.200 × 10³ to be explicit.
What rounding rule does the tool use?
It uses round-half-up away from zero: when the first dropped digit is 5 or more, the last kept digit is increased. The result always shows exactly the requested number of significant figures, padding with trailing zeros when needed.
What is E-notation?
E-notation is the calculator and programming form of scientific notation, where 'e' replaces '× 10^'. For example 6.022 × 10²³ is written 6.022e23, and 1.6 × 10⁻¹⁹ is 1.6e-19.
Related tools
Pair this with the number base converter for binary and hexadecimal, the percentage calculator for everyday math, and the unit converters across length, mass and more to put your scientific values into real-world context.