Scientific notation converter — standard form, E notation and engineering

How to use the scientific notation converter

1. Type your number in Number (standard or scientific).
2. Leave Significant figures (0 = keep all) at 0, or set a number to round.
3. Read the Scientific notation line, then the E notation, Engineering notation, Standard form and Order of magnitude lines underneath.
4. Copy the format you need. E notation such as 1.23e-7 is what calculators, spreadsheets and code expect.

What it does and when to use it

Scientific notation writes a number as a × 10ⁿ, where a is at least 1 and less than 10. It keeps very large and very small numbers readable: the mass of an electron, distances in space, or the size of a virus. Science and maths exams often ask you to convert both ways, and lab reports expect results in this form.

The converter also works backwards, writing 6.02 × 10²³ out in full. To count or adjust significant figures in a measured value, use the significant figures calculator. For powers in other bases, the logarithm calculator tells you the exponent directly, and the number to words tool spells large numbers out.

How it works

The tool reads your input as an exact fraction, so no digits are lost. It then finds n, the power of ten of the first non-zero digit, and divides by 10ⁿ to get the mantissa a. If you set significant figures, a is rounded to that many digits with round half up. Engineering notation lowers n to the nearest multiple of 3 and moves the decimal point to match. Values that never end, such as 1/3 entered as 0.(3), are shown to 15 significant figures with a note.

Step by step for 0.000000123:

1. Find the first non-zero digit: 1, in the ten-millionths place.
2. Move the decimal point right until one non-zero digit is in front: 1.23. That took 7 moves.
3. Moving right means a negative power, so n = −7.
4. Answer: 1.23 × 10⁻⁷, or 1.23e-7.

For engineering notation, −7 goes down to −9, so the point moves 2 more places: 123 × 10⁻⁹.

Worked examples

A tiny number. 0.000000123 gives Scientific notation: 1.23 × 10⁻⁷, E notation 1.23e-7, order of magnitude −7.

From scientific to plain. 6.02 × 10^23 gives Standard form: 602,000,000,000,000,000,000,000.

Rounding the speed of light. 299792458 with 3 significant figures gives 3.00 × 10⁸, and Engineering notation: 300 × 10⁶.

Trailing zeros. 45000 gives Scientific notation: 4.5 × 10⁴ and engineering 45 × 10³.

Limits and tips

• Always check the sign of the exponent: positive for numbers of 10 or more, negative for numbers below 1.
• Rounding uses round half up only. For other rules, use the rounding calculator first.
• The conversion runs entirely in your browser.