# CCS DC resistance calculator

> Compute DC resistance for any CCS grade and diameter from the IACS definition (IEC 60028: 100% IACS = 0.017241 Ω·mm²/m at 20 °C).

## Formula

resistivity = 0.017241 / (IACS fraction) Ω·mm²/m at 20 °C; resistance per metre = resistivity / cross-section.
Grades: 21 / 30 / 40 / 55% IACS. Wire range: 0.10-4.00 mm. Acceptance is the measured resistance on the MTC (ASTM B227, B910/B910M).

Interactive tool: /tools/calc-dc-resistance/