Attojoule is 1e-18 joule units.
Attojoules to Hectojoules Converter — aJ to hJ
Convert Attojoule (aJ) to Hectojoule (hJ) using the exact conversion factor (1 attojoule = 1e-20 hectojoule). See the formula, worked examples, and conversion table.
Attojoules to Hectojoules 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.
Hectojoule is 100 joule units.
Result = input x 1e-18 / 100.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Attojoules to Hectojoules
Attojoule and Hectojoule 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: Attojoule is 1e-18 joule units, and hectojoule is 100 joule units.
Formula
hectojoules = attojoules × 1e-20
This factor comes from each unit's defined relationship to the category's base unit: 1 attojoule equals 1e-18 base units, and 1 hectojoule equals 100 base units, so dividing one by the other gives the direct attojoule-to-hectojoule factor of 1e-20.
Simple example
1 aJ × 1e-20 = 1e-20 hJ
1 attojoule = 1e-20 hectojoules.
Real-world example
100 aJ × 1e-20 = 1e-18 hJ
100 attojoules = 1e-18 hectojoules.
Conversion table
| Attojoule (aJ) | Hectojoule (hJ) |
|---|---|
| 1 aJ | 1e-20 hJ |
| 10 aJ | 1e-19 hJ |
| 50 aJ | 5e-19 hJ |
| 100 aJ | 1e-18 hJ |
| 500 aJ | 5e-18 hJ |
| 1,000 aJ | 1e-17 hJ |
Reverse conversion: Hectojoule to Attojoule
1e-20 hJ × 1e+20 = 1 aJ
1e-20 hectojoules = 1 attojoules.
attojoules = hectojoules × 1e+20
For a page dedicated to this direction, see Hectojoule to Attojoule.
Understanding the Attojoule (aJ)
Attojoule is 1e-18 joule units.
Understanding the Hectojoule (hJ)
Hectojoule is 100 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many hectojoules are in 1 attojoule?
1 attojoule equals 1e-20 hectojoules, using the exact defined conversion factor rather than an estimate.
How do I convert attojoule to hectojoule?
Multiply the attojoule value by 1e-20. The converter above does this instantly to whatever precision you set.
How do I convert hectojoule back to attojoule?
Use the reverse factor: 1 hectojoule equals 1e+20 attojoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a attojoule?
Attojoule (aJ) is a unit of engineering.
What is a hectojoule?
Hectojoule (hJ) is a unit of engineering.
Is the attojoule to hectojoule conversion exact?
Yes. Both attojoule and hectojoule are defined by fixed standards rather than physical artifacts, so the factor of 1e-20 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.