Kilojoules to Attojoules Converter
Enter the energy in kilojoules below to convert it to attojoules.
Convert Kilojoules to Attojoules
Enter a value in kilojoules (kJ) to convert to attojoules (aJ).
Kilojoule to Attojoule Conversion Table
Table showing various kilojoule measurements converted to attojoules. Click any preset value or arrow to load it into the converter.
How to Convert Kilojoules to Attojoules
To convert kilojoules to attojoules, multiply the energy by the following conversion ratio: 1e+21 attojoules/kilojoule.
Since one kilojoule is equal to 1e+21 attojoules, you can use this simple formula to convert:
The energy in attojoules is equal to the energy in kilojoules multiplied by 1e+21.
For example, here's how to convert 5 kilojoules to attojoules using the formula above.
How Many Attojoules Are in a Kilojoule?
There are 1e+21 attojoules in a kilojoule, which is why we use this value in the formula above.
Our kilojoule to attojoule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Kilojoules and attojoules are both units used to measure energy. Keep reading to learn more about each unit.
What Is a Kilojoule?
A kilojoule is a unit of energy equal to 1,000 joules (J), the base unit for energy. Equal to 1,000 Joules. [1]
The kilojoule is classified as a metric and SI-compatible unit of energy. Kilojoules can be abbreviated as kJ; for example, 1 kilojoule can be written as 1 kJ.
In the metric system, "kilo" is the standard SI prefix for thousands, or 10³. This makes the kilojoule (kJ) a convenient decimal multiple of the joule (J).
In practice, kilojoules (kJ) are widely used across large-scale industrial, bulk, and macro-level energy specifications within SI metric workflows, engineering documentation, and technical data sheets.
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. [2]
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.
When converting energy between kilojoules (kJ) and attojoules (aJ), keep full floating-point precision (1 kJ = 1e+21 aJ; 1 aJ = 1e-21 kJ) during intermediate calculations and round only the final attojoule figure to match your instrument tolerance.
More Kilojoule & Attojoule Conversions
Need to calculate in the opposite direction? Use our attojoules to kilojoules calculator to switch your starting unit immediately. You can also explore related tools such as converting attojoules to kilojoules, converting kilojoules to joules, or converting kilojoules to kilocalories.
Convert from Kilojoules
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Kilojoules (kJ) to Attojoules (aJ)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Kilojoule (kJ) & Attojoule (aJ)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (kJ to aJ)