An electronvolt is the energy gained by an electron across one volt.
Electronvolts to Femtojoules Converter — eV to fJ
Convert Electronvolt (eV) to Femtojoule (fJ) using the exact conversion factor (1 electronvolt = 0.0001602177 femtojoule). See the formula, worked examples, conversion table, and common uses.
Electronvolts to Femtojoules converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
Femtojoule is 1e-15 joule units.
Result = input x 1.60217663e-19 / 1e-15.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Electronvolts to Femtojoules
Electronvolt and Femtojoule both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Electronvolt is most often used for particle physics (particle accelerator energies are often quoted in gev or tev).
Formula
femtojoules = electronvolts × 0.0001602176634
This factor comes from each unit's defined relationship to the category's base unit: 1 electronvolt equals 1.602177e-19 base units, and 1 femtojoule equals 1e-15 base units, so dividing one by the other gives the direct electronvolt-to-femtojoule factor of 0.0001602176634.
Simple example
1 eV × 0.0001602176634 = 0.0001602177 fJ
1 electronvolt = 0.0001602177 femtojoules.
Real-world example
100 eV × 0.0001602176634 = 0.0160217663 fJ
100 electronvolts = 0.0160217663 femtojoules.
Conversion table
| Electronvolt (eV) | Femtojoule (fJ) |
|---|---|
| 1 eV | 0.0001602177 fJ |
| 10 eV | 0.0016021766 fJ |
| 100 eV | 0.0160217663 fJ |
| 500 eV | 0.0801088317 fJ |
| 1,000 eV | 0.1602176634 fJ |
| 2,000 eV | 0.3204353268 fJ |
Reverse conversion: Femtojoule to Electronvolt
0.0001602177 fJ × 6241.509074 = 1.000000228 eV
0.0001602177 femtojoules = 1.000000228 electronvolts.
electronvolts = femtojoules × 6241.50907446
For a page dedicated to this direction, see Femtojoule to Electronvolt.
Understanding the Electronvolt
Electronvolt (eV) measures energy. The energy gained by a single electron accelerated through an electric potential difference of one volt — a very small amount of energy, exactly 1.602176634 × 10⁻¹⁹ joules. It is classified as a non-SI unit accepted for use with the SI, common in physics.
Where it's used: Standard unit throughout particle physics, atomic physics, and chemistry worldwide
Uses of the Electronvolt today
- Particle physics (particle accelerator energies are often quoted in GeV or TeV)
- Atomic and molecular energy levels
- Semiconductor band-gap energies
Understanding the Femtojoule (fJ)
Femtojoule is 1e-15 joule units.
Electronvolt — sources
- BIPM SI Brochure, 9th edition — Electronvolt listed as a non-SI unit accepted for use with the SI, with its exact value fixed via the elementary charge.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many femtojoules are in 1 electronvolt?
1 electronvolt equals 0.0001602177 femtojoules, using the exact defined conversion factor rather than an estimate.
How do I convert electronvolt to femtojoule?
Multiply the electronvolt value by 0.0001602176634. The converter above does this instantly to whatever precision you set.
How do I convert femtojoule back to electronvolt?
Use the reverse factor: 1 femtojoule equals 6,241.509074 electronvolts. You can also use the swap control in the converter above to flip the direction instantly.
What is a electronvolt?
Electronvolt (eV) measures energy. The energy gained by a single electron accelerated through an electric potential difference of one volt — a very small amount of energy, exactly 1.602176634 × 10⁻¹⁹ joules. It is classified as a non-SI unit accepted for use with the SI, common in physics.
What is a femtojoule?
Femtojoule (fJ) is a unit of energy.
Is the electronvolt to femtojoule conversion exact?
Yes. The energy gained by a single electron accelerated through an electric potential difference of one volt — a very small amount of energy, exactly 1.602176634 × 10⁻¹⁹ joules. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the electronvolt still used today?
Standard unit throughout particle physics, atomic physics, and chemistry worldwide