Katal (kat) to Enzyme units Converter

About this calculator

The katal (kat) is the SI unit of catalytic activity, defined as the amount of enzyme that converts one mole of substrate per second. It's enormous next to the traditional biochemistry unit, the enzyme unit (U) — one micromole of substrate converted per minute — so the exact relationship is 1 katal = 6 × 10⁷ enzyme units, which is also why lab work almost always uses microkatal (µkat) rather than the bare katal.

IUPAC and IUBMB adopted the katal as the SI-coherent unit in 1999, but biochemists, clinical laboratories, and enzymology researchers still report activity in U or U/L on assay results and product datasheets out of decades-old convention, so converting between the two systems is a routine step when comparing data from an SI-based source against a traditional lab result.