About the Scientific Notation Converter
Scientific Notation Converter turns a number into its scientific form, such as 3.45 × 10⁻⁶, and turns scientific or e-notation back into a plain decimal. Type a number in any of the usual ways: 0.00000345, 6.022e23, 1.5 × 10^-3 or just 10^-3. The tool shows scientific notation, the e-notation used by calculators and spreadsheets, engineering notation with exponents in multiples of three, the plain decimal, the power of ten and the number of significant figures in what you typed. You can also round the result to 1 to 10 significant figures. The conversion works on the digits as text, so very long numbers and extreme exponents do not lose digits, unlike a normal calculator. Nothing leaves your device.
Updated September 2026
How to use the Scientific Notation Converter
- 1Type or paste a number: plain, with an e, or with × 10^ and an exponent.
- 2Optionally choose how many significant figures to round to.
- 3Read the scientific notation in the big box and copy it with one tap.
- 4Look at the engineering notation, the plain decimal and the count of significant figures.
- 5Try the example buttons to see how different inputs are read.
Why scientific notation is used
Numbers in science span huge ranges: the distance to a star, the mass of an electron or the number of atoms in a mole. Writing them with lots of zeros is slow and easy to get wrong. Scientific notation puts the size of the number in the exponent and the precise digits in the coefficient, so that you can compare sizes at a glance and keep track of the accuracy of a measurement.
It also tells you how precise a value is. 3.00 × 10⁸ says the value is known to three significant figures, while 3 × 10⁸ says it is known to only one.
Reading and writing the notations
- Scientific: 1.2345 × 10⁴ has one digit before the point.
- E-notation: 1.2345e4 is the same number in plain text, ready for a calculator or a spreadsheet cell.
- Engineering: 12.345 × 10³ has an exponent divisible by 3 and lines up with prefixes like kilo and milli.
- Standard form is the name used in some countries for scientific notation.
- Negative exponents are for numbers between 0 and 1, and positive exponents for numbers of 10 or more.
Significant figures and rounding
Choose a number of significant figures to round the result. Rounding is done on the digits, so 0.000345678 rounded to three significant figures is 3.46 × 10⁻⁴ and 9.996 rounded to three becomes 1.00 × 10¹. Trailing zeros in the rounded result are kept, since they show the precision you asked for.
The rule for counting significant figures in the number you typed is shown, but it depends on your intent: a number like 1500 could be precise to two, three or four figures. If you mean all four, type 1500. or 1.500e3.
Related tools and tips
For arithmetic with powers, Exponent, Root and Log Calculator works out powers and roots, and Decimal to Fraction Converter changes decimals into fractions. Number to Words Converter spells out large numbers, and Unit Converter switches between units, including metric prefixes.
When you paste from a spreadsheet, remove currency symbols, and use a dot as the decimal point. Commas placed as thousands separators, as in 1,234,567, are accepted. If a number is not recognised, the tool says so instead of guessing.
Features
- Decimal to scientific notation and back
- Understands e-notation and × 10^ forms
- Engineering notation with exponents in steps of three
- Rounds to 1 to 10 significant figures
- Counts significant figures in your input
- Exact on very long numbers and big exponents
- Copy buttons for scientific and e-notation
Frequently asked questions
What is scientific notation?
It is a way of writing very large or very small numbers as a number from 1 up to (but not including) 10 multiplied by a power of ten. The speed of light, 299,792,458 metres per second, becomes 2.99792458 × 10⁸, and 0.00000345 becomes 3.45 × 10⁻⁶.
How do I convert a decimal to scientific notation?
Move the decimal point until only one non-zero digit is before it. Count the places you moved it: if you moved it left, the exponent is positive, and if you moved it right, the exponent is negative. For 0.00045 you move the point four places right to get 4.5, so the answer is 4.5 × 10⁻⁴.
What is e notation?
E-notation is the plain-text form used by calculators, spreadsheets and programming languages. 6.022e23 means 6.022 × 10²³, and 1.5e-3 means 1.5 × 10⁻³. The e stands for exponent, and it has nothing to do with the mathematical constant e.
What is engineering notation?
Engineering notation is like scientific notation, but the exponent is always a multiple of three, which matches metric prefixes such as kilo, mega, milli and micro. So 45,000 is 45 × 10³ in engineering notation and 4.5 × 10⁴ in scientific notation.
How many significant figures does my number have?
Count every digit from the first non-zero digit onwards. Zeros in the middle count, and trailing zeros count only when there is a decimal point. So 0.00340 has three significant figures, 1200 has two, and 1200.0 has five. The tool applies this rule to what you type.
Can it handle very big numbers?
Yes. The number is handled as text, so a value with dozens of digits, or a power of ten such as 10^500, is converted exactly, whereas an ordinary calculator would round it or show infinity. Only the plain decimal form is not shown in full when the exponent is beyond 300 places.