Scientific Notation Converter
Convert
Type a number in any form — a plain decimal like 0.00042, a big integer like 299792458, or E-notation like 1.5e-9 — and get it back in scientific notation (one digit before the point, ×10ⁿ), engineering notation (exponent a multiple of 3, so it lines up with kilo/mega/micro), plain E-notation for code and spreadsheets, the fully expanded decimal, and the order of magnitude. Round to a fixed number of significant figures or leave it exact. Useful for science and engineering homework, reading sensor or physics constants, and formatting numbers for papers or code. Everything runs locally in your browser.
Scientific notation
2.99792458 × 108
Engineering notation
299.792458 × 106
E-notation
2.99792458e+8
Expanded decimal
299,792,458
Order of magnitude
1 × 108
How to use
- Type or paste a number — decimals, large integers and E-notation (like 6.022e23) all work.
- Optionally choose how many significant figures to round to, or leave it on Auto.
- Copy whichever form you need: scientific, engineering, E-notation or the expanded decimal.
Frequently asked questions
- What's the difference between scientific and engineering notation?
- Scientific notation keeps one non-zero digit before the decimal point (e.g. 2.998 × 10⁸). Engineering notation forces the exponent to a multiple of 3 (e.g. 299.8 × 10⁶), so it aligns with SI prefixes like kilo (10³), mega (10⁶) and micro (10⁻⁶).
- What is E-notation?
- It's the way programming languages and spreadsheets write powers of ten: 2.998e8 means 2.998 × 10⁸. The number after 'e' is the exponent.
- What does 'significant figures' do?
- It rounds the mantissa to that many meaningful digits — e.g. 299792458 to 3 significant figures is 3.00 × 10⁸. Leave it on Auto to keep the full precision.
- Why might a very large number look slightly off?
- Numbers are handled with standard double precision (about 15–17 significant digits). Beyond that, the expanded decimal can't be represented exactly — the scientific form rounded to a few significant figures stays accurate.
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