Attojoules to Joules Converter
Enter the energy in attojoules below to convert it to joules.
Convert Attojoules to Joules
Enter a value in attojoules (aJ) to convert to joules (J).
Attojoule to Joule Conversion Table
Table showing various attojoule measurements converted to joules. Click any preset value or arrow to load it into the converter.
How to Convert Attojoules to Joules
To convert attojoules to joules, multiply the energy by the following conversion ratio: 1e-18 joules/attojoule.
Since one attojoule is equal to 1e-18 joules, you can use this simple formula to convert:
The energy in joules is equal to the energy in attojoules multiplied by 1e-18.
For example, here's how to convert 5 attojoules to joules using the formula above.
How Many Joules Are in an Attojoule?
There are 1e-18 joules in an attojoule, which is why we use this value in the formula above.
Our attojoule to joule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Attojoules and joules are both units used to measure energy. Keep reading to learn more about each unit.
What Is an Attojoule?
An attojoule is a unit of energy equal to 1/999,999,999,999,999,900 of a joule (1e-18 J). 10⁻¹⁸ Joules. [1]
The attojoule is classified as a metric and SI-compatible unit of energy. Attojoules can be abbreviated as aJ; for example, 1 attojoule can be written as 1 aJ.
When working with attojoules (aJ) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, attojoules (aJ) are widely used across fine-tolerance laboratory, analytical, and micro-scale energy measurements within SI metric workflows, engineering documentation, and technical data sheets.
What Is a Joule?
Coherent SI unit of energy and work (1 W·s = 1 N·m). It serves as a primary reference unit for measuring energy across scientific and practical applications. [2]
The joule is classified as an International System of Units (SI) unit of energy. Joules can be abbreviated as J; for example, 1 joule can be written as 1 J.
As the primary coherent reference unit for energy in this category, all other energy units are mathematically anchored to the joule (J).
In practice, joules (J) are widely used across standard energy applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.
When converting energy between attojoules (aJ) and joules (J), keep full floating-point precision (1 aJ = 1e-18 J; 1 J = 1e+18 aJ) during intermediate calculations and round only the final joule figure to match your instrument tolerance.
More Attojoule & Joule Conversions
Need to calculate in the opposite direction? Use our joules to attojoules calculator to switch your starting unit immediately. You can also explore related tools such as converting joules to attojoules, converting calories to joules, or converting kilojoules to joules.
Convert from Attojoules
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Attojoules (aJ) to Joules (J)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Attojoule (aJ) & Joule (J)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (aJ to J)