Von Klitzing constant = 25 812.807 45... Ω

Value
25 812.807 45...
Unit
Ω
Uncertainty
exact (by definition)
Copy-ready
25812.80745

The von Klitzing constant R_K = h/e², the quantised Hall resistance.

Exact since 2019, it is how national labs realise the ohm with quantum Hall devices.

NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.

Electrical, thermal and X-ray constants

Angstrom starConductance quantumCopper x unitElectron charge to mass quotientFermi coupling constantFirst radiation constantHartree energyJosephson constantLattice parameter of siliconLattice spacing of ideal Si (220)Loschmidt constant (273.15 K, 101.325 kPa)Magnetic flux quantumMolar mass constantMolar mass of carbon-12Molar Planck constantMolar volume of siliconMolybdenum x unitNeutron-proton mass differenceProton charge to mass quotientQuantum of circulationSackur-Tetrode constant (1 K, 101.325 kPa)Second radiation constantVon Klitzing constantWeak mixing angleWien frequency displacement law constantW to Z mass ratio

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All physical constants

Constants and formula sheetElectrical, thermal and X-ray constantsAll calculators