Free · Arithmetic calculators ➗

Scientific, Decimal and Engineering Forms

Round a number to selected significant figures and show matching scientific, e, expanded decimal and supported SI engineering forms.

  • Formula & worked example
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Round the number once to the chosen significant figures. Express that same rounded quantity as a scientific coefficient and integer exponent, a decimal expansion, and an engineering coefficient with an exponent divisible by three.

x ≈ m × 10^e, with1 ≤ |m| <10; engineering exponents are multiples of three.

Worked example

Enter these known values and leave the other values blank.

Precision setting
Show precision control
Number
12345
Significant figures
3
Result
Normalized scientific form: 1.23 × 10^4.
Explanation
Scientific e form: 1.23e4.
Explanation
Expanded rounded decimal: 12300.
Explanation
Engineering form with an SI prefix:
Explanation
Coefficient 12.3 k (kilo).

Assumptions and limitations

  • Accept decimal/e literals and coefficient*10^integer notation, with no more than50 significant decimal digits. The verified domain is zero or finite magnitude1e-1000 through1e308.
  • Choose a whole number from1 through15 significant figures. Halfway values round away from zero.64-digit working decimal arithmetic precedes display.
  • The precision selector reveals or hides the precision input; hiding it preserves its current value. It does not disable rounding.
  • All representations describe the same rounded quantity. Coefficient carry changes the exponent and engineering prefix when appropriate. Decimal expansions include trailing zeros according to the requested digit position.
  • The captured sixteen prefixes from yocto through yotta are preserved. An engineering prefix appears only in the original supported nonzero bands1e-24≤|rounded x|<1 and1e3≤|rounded x|<1e27. Other magnitudes retain their scientific/e/expanded forms.
  • Inputs accept decimal or e notation and bounded arithmetic expressions only when each intermediate and final value can be verified exactly as a finite decimal. Repeating fractions, functions, symbols and expressions that lose digits are rejected with guidance. Enter their finite decimal value instead; the calculator-specific magnitude and precision limits still apply.

Common questions

What happens when rounding9.999 to three significant figures?

It becomes10.0, written scientifically as1 × 10^1. All forms use the same rounded quantity, rather than keeping a scientific exponent of zero.

How does engineering notation differ from scientific notation?

Scientific notation uses a nonzero coefficient from one up to ten in absolute value. Engineering notation uses an exponent divisible by three, producing a coefficient from one up to one thousand.

Does hiding significant figures reset the number of digits?

No. It hides that control while preserving the selected precision. Reveal it again to change the value.

References

Replace five captured binary/string numerical helpers with a local decimal scientific, rounded decimal and engineering computation. Preserve all original numerical controls, significant-figure choice and all sixteen SI-prefix variants. Correct decimal rounding at powers of ten, engineering truncation, coefficient carry and prefix selection after rounding; produce every representation from the same half-away-from-zero rounded quantity. Original helper JavaScript is pinned research evidence and is never evaluated in product. Bind the converter to its complete original capture and two atomic raw/authored compiled schemas. Accept decimal/e notation and provably exact bounded finite-decimal arithmetic expressions, with no more than50 significant decimal digits; use1 through15 significant figures, zero or magnitude1e-1000 through1e308, with64-digit working arithmetic. Preserve rounded expanded decimals using the already reviewed bounded Math35 formatter. Hiding precision controls retains the current precision value, exactly as captured. Invalid/cleared input withholds all five derived presentations.

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