Scientific Notation Converter
Convert a number to scientific notation (a × 10ⁿ), E notation and engineering notation, choose how many digits to keep, or convert a coefficient and an exponent back to an ordinary decimal. It works for very large and very small numbers.
Scientific notation converter
How to use the scientific notation converter – numbers to a × 10ⁿ and back
- Choose the direction. Pick number to scientific notation, or scientific notation to number.
- Enter the number. Type a number such as 123456 or 0.000345, or enter the coefficient and the exponent.
- Set the digits. Optionally round the coefficient to 2 to 6 digits.
- Read the forms. The result shows scientific, E and engineering notation and the order of magnitude.
The form
N = a × 10ⁿ, with 1 ≤ |a| < 10 and n a whole number
Worked examples
123,456. Move the decimal point 5 places left: 1.23456 × 10⁵. In E notation that is 1.23456e5, and in engineering notation 123.456 × 10³.
0.000345. Move the decimal point 4 places right: 3.45 × 10⁻⁴, or 345 × 10⁻⁶ in engineering notation.
299,792,458 (speed of light in m/s). 2.99792458 × 10⁸.
602,214,076,000,000,000,000,000 (Avogadro constant). 6.02214076 × 10²³.
3.2 × 10⁻⁴ to a decimal. Move the decimal point 4 places left to get 0.00032.
Why scientists use it
Very large and very small numbers are easy to misread with a string of zeros. Writing the size as a power of ten shows the order of magnitude at a glance, so you can compare 10⁸ with 10⁻⁶ immediately, and the coefficient shows the precision. It also keeps calculations easier, since powers of ten multiply by adding exponents.
Significant figures
The digits in the coefficient are the significant figures. Rounding to 3 digits turns 1.23456 × 10⁵ into 1.23 × 10⁵. Use the digits option when a measurement has limited precision, because writing 123,456 suggests six reliable digits when you may only know three.
Arithmetic with powers of ten
To multiply, multiply the coefficients and add the exponents: (3 × 10⁴) × (2 × 10⁻²) = 6 × 10². To divide, divide the coefficients and subtract the exponents: (8 × 10⁵) ÷ (4 × 10²) = 2 × 10³. For addition and subtraction, first rewrite both numbers with the same exponent: 4.2 × 10³ + 3.1 × 10² = 4.2 × 10³ + 0.31 × 10³ = 4.51 × 10³. If the result is not between 1 and 10, adjust the exponent. For example, 12 × 10³ is 1.2 × 10⁴.
E notation in spreadsheets and code
Spreadsheets and programming languages display large numbers as 1.5E+10 and small ones as 3.45E-04. The E means “times ten to the power”. This is the same value as the scientific form, just typed on one line. If you are working with measurements, see the SI prefixes in NIST SP 811, and for percentage and ratio work use the percentage calculator.
Frequently asked questions
What is scientific notation?
A way to write numbers as a coefficient between 1 and 10 multiplied by a power of ten. 123,456 is 1.23456 × 10⁵.
How do I convert a number to scientific notation?
Move the decimal point until one non-zero digit is before it. The exponent is the number of places moved: positive if you moved left, negative if you moved right. 0.000345 becomes 3.45 × 10⁻⁴.
How do I convert scientific notation to a decimal?
Move the decimal point by the exponent: right for a positive exponent and left for a negative one. 3.2 × 10⁻⁴ is 0.00032.
What is E notation?
The plain-text form used by calculators, spreadsheets and programming languages. 1.5e-3 means 1.5 × 10⁻³ = 0.0015.
What is engineering notation?
A version where the exponent is always a multiple of 3, so 123,456 is 123.456 × 10³. It matches SI prefixes such as kilo, mega and milli.
How do I do arithmetic in scientific notation?
To multiply, multiply the coefficients and add the exponents. To divide, divide the coefficients and subtract the exponents. For addition, first give both numbers the same exponent.
Are trailing zeros significant?
In scientific notation you show only the digits you mean to be significant. 1.20 × 10³ has three significant figures, while 1.2 × 10³ has two.
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Sources and references
About this calculator
Written and maintained by Rashid Mehmood, founder of CalcTen. The formulas are unit-tested against hand-worked examples, and the content is reviewed whenever product sizes or guidance change. Last updated 14 November 2026. See our editorial policy.
Results are calculated from the numbers you enter and shown with the working. Rounding is applied only when displaying results. Grade and GPA scales, and weighting rules, vary by school, so confirm with your institution. Read the disclaimer.