Reference electrode potential converter
Convert a measured potential from one reference electrode to another, including the reversible hydrogen electrode at your electrolyte’s pH.
That is +0.697 V vs SHE, +0.456 V vs SCE and +0.5 V vs Ag/AgCl.
What it means
Where is that on the potential scale?
At 25 °C. Reference potentials shift with temperature and filling solution (Ag/AgCl in 3 M KCl is 0.210 V, saturated 0.197 V); junction potentials add a few mV.
Every unit
That potential against every reference
Learn
Three things worth knowing
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Add the reference
E vs SHE = E measured + E of the reference: +0.5 V vs Ag/AgCl is +0.697 V vs SHE.
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A Nernst slope
The 59 mV per pH unit is 2.303 RT/F at 25 °C, from Walther Nernst’s 1889 equation; it is why the hydrogen electrode tracks pH.
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Forgetting the pH
Converting to RHE without the electrolyte’s pH can be off by 0.8 V. Report the pH alongside the potential.
Shortcuts
Popular potential conversions
Background
About reference electrodes
An electrode potential is always measured against a reference. The textbook zero is the standard hydrogen electrode (SHE), but labs use sturdier ones: Ag/AgCl sits at +0.197 V vs SHE, the saturated calomel electrode (SCE) at +0.241 V.
Catalysis papers report against the reversible hydrogen electrode (RHE), which moves with pH: E(RHE) = E(SHE) + 0.0592 × pH. In 1 M KOH (pH 14), 0 V vs SHE is +0.83 V vs RHE.