An erg is a CGS energy unit.
Ergs to Femtojoules Converter — erg to fJ
Convert Erg (erg) to Femtojoule (fJ) using the exact conversion factor (1 erg = 100,000,000 femtojoule). See the formula, worked examples, and conversion table.
Ergs to Femtojoules 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.
Femtojoule is 1e-15 joule units.
Result = input x 1e-7 / 1e-15.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Ergs to Femtojoules
Erg and Femtojoule 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: An erg is a CGS energy unit, and femtojoule is 1e-15 joule units.
Formula
femtojoules = ergs × 100000000
This factor comes from each unit's defined relationship to the category's base unit: 1 erg equals 1e-7 base units, and 1 femtojoule equals 1e-15 base units, so dividing one by the other gives the direct erg-to-femtojoule factor of 100000000.
Simple example
1 erg × 100000000 = 100,000,000 fJ
1 erg = 100,000,000 femtojoules.
Real-world example
100 erg × 100000000 = 10,000,000,000 fJ
100 ergs = 10,000,000,000 femtojoules.
Conversion table
| Erg (erg) | Femtojoule (fJ) |
|---|---|
| 1 erg | 100,000,000 fJ |
| 10 erg | 1,000,000,000 fJ |
| 50 erg | 5,000,000,000 fJ |
| 100 erg | 10,000,000,000 fJ |
| 500 erg | 50,000,000,000 fJ |
| 1,000 erg | 100,000,000,000 fJ |
Reverse conversion: Femtojoule to Erg
1 fJ × 1e-8 = 1e-8 erg
1 femtojoule = 1e-8 ergs.
ergs = femtojoules × 1e-8
For a page dedicated to this direction, see Femtojoule to Erg.
Understanding the Erg (erg)
An erg is a CGS energy unit.
Understanding the Femtojoule (fJ)
Femtojoule is 1e-15 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many femtojoules are in 1 erg?
1 erg equals 100,000,000 femtojoules, using the exact defined conversion factor rather than an estimate.
How do I convert erg to femtojoule?
Multiply the erg value by 100000000. The converter above does this instantly to whatever precision you set.
How do I convert femtojoule back to erg?
Use the reverse factor: 1 femtojoule equals 1e-8 ergs. You can also use the swap control in the converter above to flip the direction instantly.
What is a erg?
Erg (erg) is a unit of engineering.
What is a femtojoule?
Femtojoule (fJ) is a unit of engineering.
Is the erg to femtojoule conversion exact?
Yes. Both erg and femtojoule are defined by fixed standards rather than physical artifacts, so the factor of 100000000 used above is exact to as many digits as you choose to display.
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.