Julio Lloret Lab

Energy & thermochemistry

Energy unit converter

Convert molecular, molar and macroscopic energy units without confusing the amount of substance with the energy of one entity.

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Inputs & conditions

01 / 04
Signed energies are allowed. Use a decimal point; e.g. -12.5 or 1e-3.

Basis matters. The molecular mode interprets eV and Hartree per entity and reports the equivalent per mole. It does not turn the total energy of an arbitrary sample into molar energy.

Results

SI-based

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Displayed digits are a numerical representation, not an experimental uncertainty estimate. Input conditions and method version are included in exports.

How the energy conversion works

Two modes keep the dimensional meaning explicit. In molecular mode, an energy associated with one entity is converted to its equivalent per mole of entities using the Avogadro constant. Macroscopic mode converts only total-energy units.

E(mol) = NA × E(entity)
1 eV = 1.602176634 × 10⁻¹⁹ J
1 calth = 4.184 J · 1 Wh = 3600 J

Joule, calorie and watt-hour conversions use their stated definitions. The calorie is the thermochemical calorie—not an international-table or temperature-specific calorie. Hartree energy uses the CODATA 2022 value, 4.3597447222060 × 10⁻¹⁸ J. Wavenumber is reported as the energy-equivalent quantity E/(hc), in cm⁻¹; it is not itself an SI energy unit.

Worked example

1 eV per entity = 96.4853 kJ mol⁻¹ = 23.0605 kcal mol⁻¹.

A negative reaction-energy difference remains negative on conversion. No reaction stoichiometry, charge count or electrical work is inferred from an energy value alone.

Common questions

Can I convert a sample’s total joules directly to kJ/mol?

Only when the amount of substance is known: Em = Etotal/n. The molecular mode instead defines one entity as the input basis. Keep sample energy in macroscopic mode until you have supplied the amount of substance in your own calculation.

Does converting eV to volts give a redox potential?

No. A reference electrode, charge-transfer stoichiometry and a thermodynamic model are required. Energy per elementary charge has units of volts, but this dimensional relation does not establish an electrode potential.

Sources and conventions

  1. NIST · CODATA 2022 fundamental constants
  2. NIST SP 811 · Thermochemical calorie and energy conversion factors

Method version 1.0.0 · 19 September 2026. Display precision is not measurement accuracy. Read the full scope and validation limits.