This scientific notation calculator converts any number to scientific notation, E notation and engineering notation, and back to ordinary decimal form. It counts significant figures and can round to the number of significant figures you choose.
What is scientific notation?
Scientific notation writes a number 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.
- Large numbers have a positive exponent: 45,200 = 4.52 × 10⁴.
- Small numbers have a negative exponent: 0.000452 = 4.52 × 10⁻⁴.
- E notation writes the same thing as 4.52e-4, as used by calculators and spreadsheets.
- Engineering notation uses exponents that are multiples of 3, matching units such as kilo, mega and milli: 452 × 10⁻⁶.
Significant figure rules
- All non-zero digits are significant.
- Zeros between non-zero digits are significant (1,005 has four).
- Leading zeros are not significant (0.0045 has two).
- Trailing zeros after a decimal point are significant (2.500 has four); trailing zeros in a whole number such as 4,500 are ambiguous, which scientific notation resolves.
Worked example
0.000452 becomes 4.52 × 10⁻⁴ (E notation 4.52e-4), with three significant figures. Rounded to two significant figures it is 4.5 × 10⁻⁴.
Frequently asked questions
How do I convert a number to scientific notation?
Move the decimal point until one non-zero digit is left of it. The number of places moved is the exponent: positive if you moved left, negative if you moved right.
What does 6.02e23 mean?
It is E notation for 6.02 × 10²³, Avogadro’s number to three significant figures.
How many significant figures does 4,500 have?
It is ambiguous: two, three or four. Writing 4.5 × 10³, 4.50 × 10³ or 4.500 × 10³ makes it clear.
Why use engineering notation?
Its exponents match metric prefixes, so 4.7 × 10³ ohms reads directly as 4.7 kΩ.
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Last reviewed: October 2026.