Rangdom

Convert to and from scientific notation

Type a plain decimal (like -1500000 or 0.00042) or E-notation (like 6.022e23 or 4.2E-4) to read it back as a fully expanded standard form, normalized scientific notation with one nonzero digit before the point, engineering notation with the exponent constrained to a multiple of three, and the copyable machine E-notation — all at once. The significant-figures selector controls the mantissa precision of the scientific and engineering forms; standard form and E-notation stay exact.

Values are handled as JavaScript double-precision (IEEE-754) numbers, so very large or very small magnitudes round to about 15–17 significant digits. Arbitrary-precision input, complex numbers, units, and non-decimal mantissas are out of scope.