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Scientific Notation Converter

A scientific notation converter for decimal to scientific notation and back, with E notation, engineering notation and rounding to the significant figures you choose — exact digits at any size, because the number is never squeezed into floating point.

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Runs entirely in your browser. What you enter stays on your device — nothing is sent to a server. Verify it yourself

How do you write a decimal in scientific notation?

Move the decimal point so that exactly one non-zero digit sits before it, then multiply by 10 to the power of the number of places moved — positive if you moved left, negative if right. So 123,456 is 1.23456 × 10^5 and 0.000123 is 1.23 × 10^-4.

Cost
Free, no limits
Upload
None — runs on your device
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Not required
Works offline
Yes, once loaded

How to convert a decimal to scientific notation

  1. Enter the number

    Type a decimal such as 0.000123, or scientific notation in any common form: 1.23e-4, 1.23E-4 or 1.23 × 10^-4.

  2. Choose significant figures

    Leave it on As entered to keep every digit you typed, or pick from 1 to 15 to round.

  3. Copy the form you need

    Scientific, E and engineering notation and the full decimal are listed together; each has a Copy button that copies plain text.

Examples

  • 0.0001231.23 × 10^-4 · 1.23E-4 · 123 × 10^-6

    The point moves four places right, so the exponent is -4.

  • 6.022 × 10^23602,200,000,000,000,000,000,000

    Avogadro's number, written out in full.

  • 123456 at 3 significant figures1.23 × 10^5

    Rounded half away from zero.

Key features of the Scientific Notation Converter

  • Decimal to scientific notation and back
  • E notation as calculators and spreadsheets print it
  • Engineering notation with exponents in steps of three
  • Rounding to 1–15 significant figures, half away from zero
  • Exact digits at any size — no floating-point rounding
  • Reports the significant figures and order of magnitude you typed

What it reads and writes

Input

  • Decimal (0.000123, 6,500,000)
  • E notation (1.23e-4, 1.23E+4)
  • × 10^ notation (1.23 × 10^-4, 1.23x10^4)
  • Superscript exponents (10⁻⁴)

Output

  • Scientific notation
  • E notation
  • Engineering notation
  • Full decimal

Significant figures

  • As entered
  • 1–6, 8, 10, 12 or 15

When should you use this?

  • Checking physics or chemistry homework that asks for answers in standard form.
  • Reading a spreadsheet or calculator value shown in E notation.
  • Rounding a measurement to the significant figures a lab report requires.

Limitations

  • Exponents are limited to ±1,000,000, and the full decimal is only written out for exponents up to ±1,000 — beyond that it would be thousands of zeros.
  • Trailing zeros in a whole number without a decimal point are not counted as significant, because they are ambiguous. Type 1200. to count them.
  • It converts notation; it does not do arithmetic between numbers.

Troubleshooting

It says it cannot read the number

Use one decimal point and no letters other than E. For a power of ten, write × 10^4, x10^4, *10^4 or E4.

The decimal says it is too long to write out

The exponent is beyond ±1,000. Use the scientific or E notation result, which is exact.

Common mistakes to avoid

  • Getting the exponent's sign backwards. Numbers smaller than 1 have a negative exponent; numbers 10 and above a positive one.
  • Writing a coefficient of 10 or more, such as 12.3 × 10^4. In scientific notation that should be 1.23 × 10^5.
  • Dropping trailing zeros that were measured. 2.50 has three significant figures; 2.5 has two.

Pro tips

Tips for better results

  • Comparing

    Compare exponents first, coefficients second

    To compare two numbers quickly, compare their exponents first; only if they match do the coefficients matter.

  • Spreadsheets

    Paste E notation into spreadsheets, not × 10^

    When pasting into a spreadsheet, copy the E notation — spreadsheets read 1.23E-4 as a number but treat × 10^ as text.

  • Rounding

    Round once, at the end of a calculation

    Round only at the end of a calculation. Rounding intermediate results to a few significant figures compounds the error.

What scientific notation is

Scientific notation writes a number as a coefficient between 1 and 10 multiplied by a power of ten. 123,456 becomes 1.23456 × 105 because the decimal point moves five places to the left; 0.000123 becomes 1.23 × 10-4 because it moves four places to the right. The exponent is the number's order of magnitude, which is why the form is used for quantities as far apart as the mass of an electron and the distance between galaxies.

In British schools the same thing is taught as standard form. Be careful with that name in American material, where "standard form" often means the ordinary decimal instead.

E notation and engineering notation

E notation is the same idea written on one line: 1.23E-4 means 1.23 × 10-4. It is what calculators, spreadsheets and most programming languages print when a number is too large or small for the display. Engineering notation restricts the exponent to multiples of three, so 0.000123 is 123 × 10-6 — which reads directly as 123 micro-units, matching the SI prefixes kilo, mega, milli and micro.

Significant figures

Significant figures are the digits that carry meaning about precision, starting from the first non-zero digit. 0.004560 has four: the leading zeros only place the decimal point, while the final zero says the value was measured to that place. A whole number such as 1200 is ambiguous — it might have two, three or four significant figures — so the converter counts only the 12 unless you type a decimal point (1200.), and tells you when that has happened.

Rounding to a chosen number of significant figures rounds half away from zero, and pads with zeros when you ask for more digits than you typed, so 2.5 to four significant figures is 2.500 × 100.

Privacy

The Scientific Notation Converter runs entirely in your browser. What you enter and the result it produces stay on your own device — nothing is sent anywhere, because nothing needs to be.

You can confirm this rather than take our word for it: open your browser’s developer tools, watch the Network tab, and use the tool. No request carries your input. It also keeps working with the connection off.

Details are in the privacy policy.

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Scientific Notation Converter — questions

How do I convert a decimal to scientific notation?

Move the decimal point until one non-zero digit is left in front of it, and count the places moved. Moving left gives a positive exponent and moving right a negative one: 4,500 is 4.5 × 10^3 and 0.0045 is 4.5 × 10^-3.

What does E mean in a number like 6.02E23?

E stands for "times ten to the power of". 6.02E23 is 6.02 × 10^23, and 1.5E-7 is 1.5 × 10^-7. Paste either form into the converter to see the full decimal.

How many significant figures does a number have?

Count from the first non-zero digit to the last digit written. Zeros between other digits count, leading zeros never do, and trailing zeros count only after a decimal point. The converter reports the count for whatever you type.

Can it handle very large or very small numbers?

Yes. Digits are handled as text, not as a floating-point number, so a 30-digit integer converts without losing any digits. Exponents up to ±1,000,000 are accepted, and the plain decimal is written out for exponents up to ±1,000.

What is the difference between scientific and engineering notation?

Scientific notation keeps one digit before the point (1.23 × 10^5); engineering notation chooses an exponent that is a multiple of three and lets the coefficient run from 1 to 999 (123 × 10^3), which lines up with prefixes such as kilo and mega.

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