Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 cal | 2.612e+16 eV | |
| 0.01 cal | 2.612e+17 eV | |
| 0.1 cal | 2.612e+18 eV | |
| 1 cal | 2.612e+19 eV | |
| 5 cal | 1.306e+20 eV | |
| 10 cal | 2.612e+20 eV | |
| 50 cal | 1.306e+21 eV | |
| 100 cal | 2.612e+21 eV | |
| 1000 cal | 2.612e+22 eV |
Formula: Electron Volt = Calorie × 2.6117e19
Multiply any calorie value by 2.6117e19 to get electron volt.
Reverse: Calorie = Electron Volt × 3.8289e-20
Common calorie values — factor: 1 cal = 2.6117e19 eV
| Calorie (cal) | Electron Volt (eV) | Context |
|---|---|---|
| 1 cal | 2.612e+19 eV | 1 cal |
| 5 cal | 1.306e+20 eV | 5 cal |
| 10 cal | 2.612e+20 eV | Small candy |
| 50 cal | 1.306e+21 eV | 50 cal |
| 100 cal | 2.612e+21 eV | Short walk |
| 500 cal | 1.306e+22 eV | Snack |
| 1,000 cal | 2.612e+22 eV | Light meal |
| 5,000 cal | 1.306e+23 eV | Meal |
| 1e+04 cal | 2.612e+23 eV | Large meal |
| 5e+04 cal | 1.306e+24 eV | Daily intake fraction |
| 1e+05 cal | 2.612e+24 eV | 100 kcal |
| 5e+05 cal | 1.306e+25 eV | 500 kcal workout |
| 1e+06 cal | 2.612e+25 eV | 1 Mcal |
| 1.000e+09 cal | 2.612e+28 eV | 1 Gcal |
| 1.000e+12 cal | 2.612e+31 eV | 1 Tcal |
1 cal = 2.6117e19 eV. Memorize for instant estimates.
Use 2.6117e19 as a quick mental multiplier.
Multiply result by 3.8289e-20 to recover the original cal value.
Works with beam energies, collision products, and mass-energy in eV.
Designs band gap structures — silicon band gap is 1.12 eV.
Selects tube voltage in keV for optimal diagnostic X-ray imaging.
Optimizes solar cell efficiency based on photon energy in eV.
Calculates nuclear binding energies and decay Q-values in MeV.
Measures work function and ionization energy in electron volts.
The calorie (cal) was defined in 1824 as the heat needed to raise 1 gram of water by 1°C. There are two versions: the small calorie (cal = 4.184 J) and the large calorie or kilocalorie (kcal = 4,184 J), which is the 'Calorie' used in nutrition.
The calorie remains standard in chemistry for heat of reaction measurements. In the US, food packaging uses 'Calories' (with capital C) which are actually kilocalories — a persistent source of confusion.
Interesting fact: The confusion between cal and kcal means that a food label saying '200 Calories' actually means 200 kcal = 200,000 cal = 836,800 joules. The SI unit for food energy is the kilojoule.
The electron volt (eV) is the energy gained by a single electron accelerating through a potential difference of one volt, equal to approximately 1.602 × 10⁻¹⁹ joules. It was formally adopted as a unit by the IEC in 1930.
Electron volts are the standard energy unit in atomic physics, particle physics, and semiconductor engineering. Chemical bond energies are a few eV; X-ray photons are kiloelectron volts (keV); particle accelerators measure GeV and TeV.
Interesting fact: The Large Hadron Collider accelerates protons to 6.8 TeV (6.8 × 10¹² eV). Visible light photons have energies of 1.8–3.1 eV. The rest mass energy of an electron is 511 keV.
Converting calorie to electron volt is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 cal = 1.3059e20 eV and 10 cal = 2.6117e20 eV. Reverse: 1 eV = 3.8289e-20 cal. Exact factor: 1 cal = 2.6117e19 eV.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.