Scientific Notation Converter — All Number Formats
Convert any number to scientific notation, engineering notation, E-notation, and SI prefix form simultaneously. Choose significant figures and copy each result with one click. Runs in your browser.
⏱ 5 min read · Complete guide below
Enter a number above to see all notation formats.
How the Scientific Notation Converter Works
- 1Enter any number in the input — decimal, E-notation (1.5e8), or ×10^ format (1.5×10^8).
- 2Select your preferred significant figures (2–6).
- 3All five formats appear instantly: decimal, scientific, engineering, E-notation, and SI prefix.
- 4Click Copy next to any row to copy that notation to the clipboard.
When to Use Each Notation
Use scientific notation in physics and chemistry papers when exact precision matters. Use engineering notation in electronics and electrical engineering, where values align with component ratings (k ohm, mF, MHz). Use E-notation in code and spreadsheets. Use SI prefixes for everyday measurements and instrument readings.
Why Scientific Notation Exists
Science routinely deals with numbers that are absurd to write out in full. The distance to the nearest star is about 40,000,000,000,000 kilometres; the mass of an electron is 0.00000000000000000000000000000091 kilograms. Writing, reading, or comparing numbers like these in ordinary decimal form is error-prone — miscount the zeros and you are off by a factor of ten. Scientific notation solves this by expressing every number as a coefficient between 1 and 10 multiplied by a power of ten, so those two values become a tidy 4 × 10¹³ and 9.1 × 10⁻³¹. The exponent captures the scale at a glance, and the coefficient carries the meaningful digits.
How to Read and Write It by Hand
The rule is simple: move the decimal point until exactly one non-zero digit sits to its left, then count how many places you moved it. Moving left (for large numbers) gives a positive exponent; moving right (for small numbers) gives a negative one. Turning 48,300 into scientific notation, you shift the point four places left to get 4.83, so the answer is 4.83 × 10⁴. For 0.0067 you shift three places right to get 6.7, giving 6.7 × 10⁻³. A positive exponent therefore always means a number bigger than one, and a negative exponent a number smaller than one — a quick sanity check that catches most mistakes.
Significant Figures and Honest Precision
One of scientific notation's quiet virtues is that it makes precision explicit. The coefficient shows exactly which digits are meaningful, so 3.00 × 10⁸ clearly claims three significant figures while 3 × 10⁸ claims only one. This matters in real measurement: reporting more digits than your instrument can resolve implies a false confidence. When you use the significant-figures control here, you are choosing how much precision to keep — a good habit is to match it to the least precise value in your calculation rather than copying whatever a calculator happens to display.
Scientific Notation Tips
Speed of light: 3 × 10⁸ m/s
Try entering 299792458 — it converts to 2.998 × 10⁸ in scientific notation. The 3 × 10⁸ approximation is accurate to 1 sig fig and is the standard physics shorthand.
Avogadro's number: 6.022 × 10²³
Enter 6.022e23. This is the number of molecules in one mole of a substance, used constantly in chemistry. It is also a good test for very large number inputs.
Planck's constant: 6.626 × 10⁻³⁴ J·s
Enter 6.626e-34 — the quantum of action used in E=hf calculations. Very small numbers like this are where scientific notation is indispensable for clarity.
Match precision to your source
If your given value has 3 significant figures (e.g. 9.81 m/s²), set sig figs to 3. Reporting more sig figs than the measurement contains implies false precision.
Frequently Asked Questions
What is the difference between scientific and engineering notation?
Scientific notation uses any integer exponent (e.g. 1.23 × 10⁷). Engineering notation restricts the exponent to multiples of 3 (3, 6, 9, -3, -6…) so that coefficients align with SI prefixes like kilo, mega, and milli.
What is E-notation?
E-notation (or computer scientific notation) writes the exponent after the letter "e": 1.23e7 means 1.23 × 10⁷. It is used in programming languages and spreadsheets where superscripts are not available.
What are SI prefixes?
SI prefixes are standardised multiplier names for powers of 1000: kilo (k) = 10³, mega (M) = 10⁶, giga (G) = 10⁹, milli (m) = 10⁻³, micro (μ) = 10⁻⁶, nano (n) = 10⁻⁹, etc.
What input formats are accepted?
The converter accepts standard decimal (12345.67), E-notation (1.2e4), and the × 10^ format (1.2×10^4). Spaces are ignored. Negative numbers are also supported.
What does significant figures mean?
Significant figures (sig figs) are the meaningful digits in a number. The converter lets you choose 2–6 sig figs to control the precision of the output without changing the magnitude.
Why does the SI prefix output show a multiplier?
For numbers outside the standard SI prefix range (10⁻¹⁸ to 10²⁴), or for numbers exactly at base 10⁰, the output shows the raw multiplier instead of a prefix letter since no standard SI prefix applies.
How do I convert a number to scientific notation by hand?
Move the decimal point until exactly one non-zero digit is to its left, and count the places you moved it. Moving left (for numbers greater than one) gives a positive exponent; moving right (for numbers less than one) gives a negative exponent. For example, 48,300 becomes 4.83 × 10⁴, and 0.0067 becomes 6.7 × 10⁻³. The digits you keep form the coefficient and the count becomes the power of ten.
What is the coefficient (or mantissa)?
The coefficient — sometimes called the mantissa or significand — is the part of the number written before the "× 10". In proper scientific notation it is always at least 1 and less than 10, so in 6.022 × 10²³ the coefficient is 6.022. It carries the significant digits of the value, while the power of ten records the magnitude. Engineering notation relaxes this rule, allowing coefficients from 1 up to 1000 so the exponent can stay a multiple of three.
How do negative exponents work?
A negative exponent means the number is smaller than one — you divide by that power of ten instead of multiplying. So 10⁻³ equals 1/1000 = 0.001, and 6.7 × 10⁻³ equals 0.0067. The more negative the exponent, the smaller the number. This is how scientific notation expresses tiny quantities like the size of an atom or the charge of an electron without a long string of leading zeros.
Can I convert very large or very small numbers?
Yes. The converter handles the full range of double-precision numbers, which comfortably covers everything from subatomic scales (around 10⁻³⁰) to astronomical ones (around 10³⁰) and well beyond. For values outside the range covered by standard SI prefixes, the SI output falls back to showing the raw power of ten, while the scientific and E-notation outputs remain exact.