Scientific Notation Converter

Convert decimal, scientific, E-notation, and engineering notation

Scientific notation writes very large or very small numbers as a mantissa multiplied by a power of 10 — 6,371,000 becomes 6.371 × 10⁶. E-notation is the same idea written in plain-text-friendly form: 6.371e6, the format calculators, spreadsheets, and programming languages use. Engineering notation is a variant of scientific notation where the exponent is always a multiple of 3, which lines up neatly with SI prefixes like kilo, mega, and micro. This tool converts between all of them in both directions.

How to use the scientific notation converter

• In "Decimal → Scientific" mode, type any decimal number and choose how many significant figures you want in the result.
• You'll instantly get the scientific notation, E-notation, engineering notation (with its matching SI prefix when there is one), and the full exact decimal expansion.
• In "Scientific → Decimal" mode, paste a number in E-notation (like 6.022e23) or written-out scientific notation (like 6.022 x 10^23), and get the full plain decimal number back, with the alternate notations shown alongside it.
• Copy the full set of results with one click for use in a report, spreadsheet, or homework.

Real-world uses

Students and scientists use this constantly for physics and chemistry problems involving very large numbers (distances in astronomy, Avogadro's number) or very small ones (wavelengths, atomic masses). Engineers reach for engineering notation specifically because its multiples-of-3 exponents map directly onto everyday units like kilometers, milliamps, and nanoseconds — this tool shows both forms side by side so you don't have to convert by hand.

Frequently asked questions

What's the difference between scientific notation and E-notation?

They represent the same value — scientific notation is written with a proper × 10ⁿ, while E-notation replaces that with a plain-text "e" (like 6.371e6), which is easier to type and is what most calculators, spreadsheets, and programming languages actually output.

Why is engineering notation different from scientific notation?

Standard scientific notation always keeps the mantissa between 1 and 10, while engineering notation instead forces the exponent to be a multiple of 3 (even if that means the mantissa isn't between 1 and 10) — this makes it line up directly with SI unit prefixes like kilo (10³), mega (10⁶), and milli (10⁻³).

How many significant figures should I use?

It depends on your source data's precision — scientific and engineering measurements are usually reported with 2-6 significant figures reflecting how precisely the value was actually measured; adding more digits than your original data supports implies false precision.

Can I convert a very small number like 0.00000012?

Yes — both very large and very small numbers work in either direction; small decimals convert to a negative exponent (0.00000012 becomes 1.2 × 10⁻⁷), and this tool handles that exactly the same way as large numbers.

Does this tool accept numbers already in scientific notation as input?

Yes — switch to "Scientific → Decimal" mode and paste values like "1.23e-4" or "1.23 x 10^-4" and the tool converts them straight back to a full plain decimal number.