Microsiemens per Centimetre to %IACS (µS/cm to %IACS)

Formula

%IACS = µS/cm ÷ 5800000000

Derivation from SI units:

• 1 µS/cm = 10⁻⁴ S/m = 0.001 mS/cm
• 100 %IACS = 58 m/(Ω·mm²) = 58 MS/m at 20 °C, so 1 %IACS = 0.58 MS/m (exact)
• 1 µS/cm = 0.0001 S/m ÷ 580000 S/m per %IACS = 1.724137931034 × 10⁻¹⁰ %IACS

Both units are defined exactly, so the factor is exact. Microsiemens per Centimetre definition: microsiemens per centimetre; %IACS definition: percent IACS.

Worked examples

1. A reading of 10 µS/cm converts to 1.724137931 × 10⁻⁹ %IACS.
   10 µS/cm × 1.724137931 × 10⁻¹⁰ = 1.724137931 × 10⁻⁹ %IACS
2. A value of 500 µS/cm is 8.620689655 × 10⁻⁸ %IACS.
   500 µS/cm × 1.724137931 × 10⁻¹⁰ = 8.620689655 × 10⁻⁸ %IACS

Where it's used

Microsiemens per Centimetre are used for drinking, boiler and cooling water quality, while percent IACS appear in copper and aluminium conductor grading. Both measure electrical conductivity, so the conversion is a fixed factor.

Microsiemens per Centimetre to other electrical conductivity units

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
• Copper Wire Tables, NBS Handbook 100 (International Annealed Copper Standard), National Bureau of Standards (now NIST) , Section 1.2, International Annealed Copper Standard.

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.