Energy Converter: eV to kJ/mol, Joule, calorie, kWh and wavenumber

Quick conversion across physics, chemistry, biology and geosciences: bond energies, band gaps and ionization energies in eV ↔ kJ/mol, Arrhenius activation energies (kJ/mol ↔ kcal/mol), pressure–volume work (L·atm ↔ J), statistical thermodynamics (comparing a barrier with RT at a given temperature), spectroscopy (transitions in cm⁻¹ ↔ kJ/mol), computational chemistry (Hartree, Eₕ) and metabolic or nutritional energy (kcal, kWh).

Pick the mode with the Energy / Molar energy selector. You type a value, choose the unit of the value and the unit of the result, and the page shows the general formula for that pair and, below it, the same operation with your number substituted. “Show all equivalents” opens the value across the 15 units of Energy mode —8 in molar mode— and the significant-figures selector switches between 6 and 10. Molar energy mode is the differentiator: it turns per-particle energy into per-mole energy —a 1 eV band gap equals 96.4853 kJ/mol, which is the Faraday constant read as energy, and a 1000 cm⁻¹ infrared transition equals 11.9627 kJ/mol— using Avogadro's number and the hc product. It includes the thermal energy RT, whose value depends on temperature: that is why molar mode carries its own temperature field, defaulting to 298.15 K (25 °C), handy for judging whether a barrier is large or small compared with thermal agitation. A precision detail: the thermochemical calorie (4.184 J) is treated as a distinct unit from the International Table calorie (4.1868 J), something most converters conflate. Because a molar energy and a total energy have different dimensions, switching modes clears the field instead of reinterpreting the number you wrote.

The input must be a finite decimal, with optional scientific notation: an incomplete form such as 1e, or text containing letters, is rejected as a whole instead of being trimmed. RT needs a temperature above 0 K, where thermal energy vanishes and the unit can no longer divide. If an equivalent overflows the floating-point range —1e300 J expressed in eV, for instance— that row shows “—” without invalidating the conversion you asked for. The tool converts units: it does not estimate uncertainty, does not compute the energy of a reaction or a process, and does not bridge the two modes, since doing so would require knowing how many particles sit behind a total energy.

• Band gap · 1 eV per particle1 eV = 96.4853 kJ/mol = 23.0605 kcal/mol
• Infrared transition · 1000 cm⁻¹1000 cm⁻¹ = 11.9627 kJ/mol
• Thermal energy at 25 °C · T = 298.15 K1 RT = 2.47896 kJ/mol
• The two calories · work and heat1 kcal = 4.184 kJ; 1 cal·IT = 4.1868 J; 1 L·atm = 101.325 J