Scientific Notation Converter
Convert any number to scientific (and E) notation, and back.
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Enter a number in ordinary form, such as 0.00042, or in E-notation, such as 6.02e23, and this converter shows it in scientific notation with a proper superscript power of ten, in the E-notation used by calculators and code, and as a standard number. It is aimed at physics and chemistry homework, lab reports and anyone reading very large or very small values off a spreadsheet.
How a number is converted
The converter finds the exponent as the whole-number part of log₁₀ of the number, then divides the number by 10 to that power to get the mantissa (also called the coefficient). The mantissa is rounded to at most six decimal places.
| You enter | Scientific | E notation |
|---|---|---|
| 0.00042 | 4.2 × 10⁻⁴ | 4.2e-4 |
| 6.02e23 | 6.02 × 10²³ | 6.02e23 |
| 140000000 | 1.4 × 10⁸ | 1.4e8 |
| 299792458 | 2.997925 × 10⁸ | 2.997925e8 |
| -0.000000123 | -1.23 × 10⁻⁷ | -1.23e-7 |
The fourth row shows the rounding: the speed of light, 299,792,458 m/s, has an exact mantissa of 2.99792458, which is shortened to six decimals.
Doing it by hand
Normalised scientific notation has exactly one non-zero digit before the decimal point, so the mantissa is at least 1 and less than 10. Move the decimal point until that is true and count the moves:
- 0.00042 → move the point 4 places right to get 4.2, so the exponent is −4.
- 140,000,000 → move it 8 places left to get 1.4, so the exponent is +8.
Moving right gives a negative exponent (a number smaller than 1); moving left gives a positive one.
Reading E-notation
The letter e stands for "times ten to the power of". So 1.6e-19 means 1.6 × 10⁻¹⁹, about the charge of an electron in coulombs, and 6.02e23 is Avogadro's number. Excel displays the same idea as 6.02E+23, scientific calculators often show a small "×10" or "E", and programming languages such as Python and JavaScript accept 6.02e23 directly as a number. Typing values in E-notation is the fastest way to enter them here too.
Significant figures and engineering notation
Scientific notation makes precision visible. Writing 1.40 × 10⁸ says the value is known to three significant figures, while 1.4 × 10⁸ claims only two. The converter drops trailing zeros, so add them back if your answer must show a specific number of significant figures.
Engineering notation is a close relative that only uses exponents divisible by three, matching the prefixes kilo, mega and giga. 4.2 × 10⁻⁴ becomes 420 × 10⁻⁶ (420 micro-units). This tool produces scientific notation, not engineering notation.
Input tips and limits
- Thousands separators are ignored. "1,500" and "1,50,000" are read as 1500 and 150000, so you can paste figures as they appear in a report. Use a dot, not a comma, for decimals.
- The Standard line is best for expanding large E-values, for example 1.4e8 into 14,00,00,000 (14 crore) on an Indian-English browser. Very small values are written out in full too, so 4.2e-4 appears as 0.00042.
- Zero is shown as 0 × 10⁰.
To say a large result aloud in lakh and crore or in millions, paste the digits into the number to words converter.