Femtojoule is 1e-15 joule units.
Femtojoules to Electronvolts Converter — fJ to eV
Convert Femtojoule (fJ) to Electronvolt (eV) using the exact conversion factor (1 femtojoule = 6,241.509074 electronvolt). See the formula, worked examples, conversion table, and common uses.
Femtojoules to Electronvolts converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
An electronvolt is the energy gained by an electron across one volt.
Result = input x 1e-15 / 1.60217663e-19.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Femtojoules to Electronvolts
Femtojoule and Electronvolt both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: Femtojoule is 1e-15 joule units, and an electronvolt is the energy gained by an electron across one volt.
Formula
electronvolts = femtojoules × 6241.50907446
This factor comes from each unit's defined relationship to the category's base unit: 1 femtojoule equals 1e-15 base units, and 1 electronvolt equals 1.602177e-19 base units, so dividing one by the other gives the direct femtojoule-to-electronvolt factor of 6241.50907446.
Simple example
1 fJ × 6241.509074 = 6,241.509074 eV
1 femtojoule = 6,241.509074 electronvolts.
Real-world example
100 fJ × 6241.509074 = 624,150.9074 eV
100 femtojoules = 624,150.9074 electronvolts.
Conversion table
| Femtojoule (fJ) | Electronvolt (eV) |
|---|---|
| 1 fJ | 6,241.509074 eV |
| 10 fJ | 62,415.09074 eV |
| 50 fJ | 312,075.4537 eV |
| 100 fJ | 624,150.9074 eV |
| 500 fJ | 3,120,754.537 eV |
| 1,000 fJ | 6,241,509.074 eV |
Reverse conversion: Electronvolt to Femtojoule
1 eV × 0.0001602176634 = 0.0001602177 fJ
1 electronvolt = 0.0001602177 femtojoules.
femtojoules = electronvolts × 0.0001602176634
For a page dedicated to this direction, see Electronvolt to Femtojoule.
Understanding the Femtojoule (fJ)
Femtojoule is 1e-15 joule units.
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
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 electronvolts are in 1 femtojoule?
1 femtojoule equals 6,241.509074 electronvolts, using the exact defined conversion factor rather than an estimate.
How do I convert femtojoule to electronvolt?
Multiply the femtojoule value by 6241.509074. The converter above does this instantly to whatever precision you set.
How do I convert electronvolt back to femtojoule?
Use the reverse factor: 1 electronvolt equals 0.0001602177 femtojoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtojoule?
Femtojoule (fJ) is a unit of engineering.
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.
Is the femtojoule to electronvolt 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.
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.