Scientific Notation Converter

Convert decimal ↔ scientific notation. Standard form a × 10^b with 1 ≤ |a| < 10.

Inputs

Result

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How to use this calculator

  • Pick direction.
  • Enter values.
  • Calculator normalizes mantissa to 1 ≤ a < 10.

About this calculator

Scientific notation expresses very large or small numbers as a × 10^b with 1 ≤ |a| < 10. 0.000456 = 4.56 × 10⁻⁴; 6.022 × 10²³ = 602,200,000,000,000,000,000,000 (Avogadro's number). Programmers and engineers use "e-notation" (1.5e-4 = 1.5 × 10⁻⁴). For everyday numbers (1 to 10000), it's overkill; for atomic-to-cosmic scales, essential.

How it works — the formula

x = a × 10ⁿ with 1 ≤ |a| < 10 (normalised form) or 0 when x = 0

Scientific notation expresses a number as a coefficient (mantissa) between 1 and 10 multiplied by an integer power of 10. The "normalised" form is unique for non-zero numbers; engineering notation is similar but constrains n to multiples of 3 to align with SI prefixes (kilo, mega, giga). Scientific notation is the IEEE 754 standard's representation of floating-point numbers, with binary instead of decimal radix.

Sources: NIST SP 811 — Guide for the Use of the International System of Units (SI), §6 Letter symbols · IUPAC Compendium of Chemical Terminology ("Gold Book", searchable at goldbook.iupac.org) — scientific notation · Wolfram MathWorld — Scientific notation

Worked examples

Example 1
Normal form
Inputs:
x = 12,345
Output:
1.2345 × 10⁴
Example 2
Small magnitude
Inputs:
x = 0.000567
Output:
5.67 × 10⁻⁴
Example 3
Engineering form (n multiple of 3)
Inputs:
x = 12,345
Output:
12.345 × 10³ — engineering form pairs with kilo prefix

Limitations

  • IEEE 754 double precision provides 15–17 significant decimal digits — values requiring more digits cannot be represented exactly.
  • Very large or small magnitudes (|n| > 308 in double precision) overflow / underflow to ±Infinity or 0.
  • Coefficient must satisfy 1 ≤ |a| < 10 for the canonical form; some engineering uses normalize differently.
  • Different display conventions: 1.23e4, 1.23E4, 1.23 × 10⁴ — semantically identical but visually distinct.

Conversion is exact for representable values; trailing-digit differences vs hand calculations come from binary-decimal floating-point round-off.

Frequently asked

Why 1 ≤ |a| < 10?+
Standard "scientific notation" canonical form. Other normalizations (engineering: exponents only multiples of 3) exist for specific contexts.
What's "engineering notation"?+
Exponent restricted to multiples of 3 (matches SI prefixes: kilo, mega, giga). 1500 = 1.5 × 10³ in scientific = 1.5 × 10³ in engineering. Same.
How precise?+
JavaScript Number gives ~15 significant digits. Beyond that, you'd need a big-number library.
How is this used?+
Physics, chemistry, astronomy — most quantities span 30+ orders of magnitude. Scientific notation prevents zero-counting errors.
Negative exponents?+
Mean very small numbers. 10⁻⁹ = nano (one billionth). 10⁻¹² = pico.

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