What is scientific notation?
A number written as a × 10ⁿ, where a is at least 1 and less than 10, and n is a whole number. It makes very large and very small numbers easy to read and compare.
Examples
- 0.000456789 with 3 significant figures = 4.57 × 10⁻⁴.
- The speed of light, 299,792,458 m/s ≈ 3.00 × 10⁸ m/s.
How to convert by hand
- Move the decimal point until only one non-zero digit is left of it.
- Count how many places you moved it: that is n.
- Moving left gives a positive n (big numbers); moving right gives a negative n (small numbers).
Engineering notation
Like scientific notation, but the exponent is always a multiple of 3 (10³, 10⁻⁶…), which matches prefixes such as kilo, mega, milli and micro.
Frequently asked questions
Which zeros are significant?
Zeros between other digits and trailing zeros after a decimal point are significant. Leading zeros (as in 0.0045) are not.
What does 4.57E-4 mean?
It is how calculators and spreadsheets write 4.57 × 10⁻⁴.
Can I type a number in E notation?
Yes. Type it as 1.5e-7 or 6.02e23.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.