This converter supports common SI prefixes from nano (10⁻⁹) through tera (10¹²), plus the unprefixed base unit. Select the source and target prefix to apply 10^(source exponent − target exponent). The Prefix Table lists the supported subset, not all 24 SI prefixes. The complete SI range extends from quecto (10⁻³⁰) to quetta (10³⁰).
How the Metric Prefix Converter works
Every SI prefix is defined as an exact power of ten relative to the base unit (the unprefixed unit, exponent 0). Converting between two prefixes is a single power-of-ten shift: result = value × 10^(fromExponent − toExponent). Because the shift is always an exact power of ten, metric prefix conversions never introduce rounding error the way imperial-to-metric conversions can — the math is exact to the precision of floating-point arithmetic.
Inputs and what they mean
Limits and edge cases
This calculator handles decimal SI metric prefixes only — it does not convert binary/data-storage prefixes like kibibyte (KiB) or mebibyte (MiB), which use powers of 1,024 rather than powers of 10. For byte-based conversions, use the dedicated Data Storage calculator. Very large or very small results (beyond roughly 10⁹ or below 10⁻⁶) are automatically shown in exponential notation on the Convert tab to preserve readability, and the Scientific Notation tab always shows the normalized a×10^b form regardless of magnitude.