Scientific Notation Converter

Decimal, scientific and E-notation

Scientific notation writes a number as a coefficient multiplied by a power of ten, with the coefficient kept between 1 and 10. For example, the speed of light is about 2.998 × 10⁸ metres per second, and a tiny length might be 1.6 × 10⁻⁹ metres. This format makes very large and very small numbers easy to read, compare and multiply, because you work with a short coefficient and simply add or subtract exponents. This converter turns ordinary decimals into scientific notation and back, and also shows the matching E-notation that calculators and programming languages use, where the same value is written 2.998e8 or 1.6e-9.

Type a value in either the decimal box or the E-notation box and the other updates instantly, so you can convert in whichever direction you need. The decimal field accepts plain numbers, and the E-notation field accepts forms like 6.022e23 or 9.1e-31. Switching between the two views is common when moving between handwritten work, spreadsheets and code, each of which prefers a different style for the same underlying number.

Significant figures and rounding

Significant figures are the digits that carry real precision, counted from the first non-zero digit. Choosing a number of significant figures controls how the scientific form is rounded: asking for four significant figures turns 0.000123456 into 1.235 × 10⁻⁴. This matters in science and engineering, where reporting more digits than you measured overstates precision and reporting too few throws away information. The converter lets you set the figure count and rounds the coefficient accordingly while leaving the exponent correct.

Accuracy and privacy

Conversions use standard double-precision arithmetic, which is exact for the digits people normally work with; numbers near the limits of floating point can show tiny rounding differences in the final digit. The exponent is always computed from the magnitude of the value, so leading and trailing zeros are handled correctly. Everything runs locally in your browser, and the values you type are never uploaded, stored or shared with any server.