eV to Ha Converter - Electron Volt to Hartree

Conversion derivation

Express both eV and Ha in the same base unit J (joule), then cancel the shared base unit.

1. 1

   Rewrite eV in the base unit

   $$1\mathrm{eV}=1.60217663\times 10^{-19}\mathrm{J}$$
2. 2

   Rewrite Ha in the base unit

   $$1\mathrm{Ha}=4.35974472\times 10^{-18}\mathrm{J}$$
3. 3

   Forward conversion

   $$\begin{array}{rl}1\mathrm{eV}& =\frac{1.60217663\times 10^{-19}\cancel{\mathrm{J}}}{4.35974472\times 10^{-18}\cancel{\mathrm{J}}}\times 1\mathrm{Ha}\\ & =\frac{1.60217663\times 10^{-19}}{4.35974472\times 10^{-18}}\mathrm{Ha}\\ & =0.036749322176\mathrm{Ha}\end{array}$$
4. 4

   Reverse conversion

   $$\begin{array}{rl}1\mathrm{Ha}& =\frac{4.35974472\times 10^{-18}\cancel{\mathrm{J}}}{1.60217663\times 10^{-19}\cancel{\mathrm{J}}}\times 1\mathrm{eV}\\ & =\frac{4.35974472\times 10^{-18}}{1.60217663\times 10^{-19}}\mathrm{eV}\\ & =27.211386246\mathrm{eV}\end{array}$$