Attojoules to Kilojoules Converter
Enter the energy in attojoules below to convert it to kilojoules.
Convert Attojoules to Kilojoules
Enter a value in attojoules (aJ) to convert to kilojoules (kJ).
Attojoule to Kilojoule Conversion Table
Table showing various attojoule measurements converted to kilojoules. Click any preset value or arrow to load it into the converter.
How to Convert Attojoules to Kilojoules
To convert attojoules to kilojoules, multiply the energy by the following conversion ratio: 1e-21 kilojoules/attojoule.
Since one attojoule is equal to 1e-21 kilojoules, you can use this simple formula to convert:
The energy in kilojoules is equal to the energy in attojoules multiplied by 1e-21.
For example, here's how to convert 5 attojoules to kilojoules using the formula above.
How Many Kilojoules Are in an Attojoule?
There are 1e-21 kilojoules in an attojoule, which is why we use this value in the formula above.
Our attojoule to kilojoule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Attojoules and kilojoules 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 Kilojoule?
A kilojoule is a unit of energy equal to 1,000 joules (J), the base unit for energy. Equal to 1,000 Joules. [2]
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.
When converting energy between attojoules (aJ) and kilojoules (kJ), keep full floating-point precision (1 aJ = 1e-21 kJ; 1 kJ = 1e+21 aJ) during intermediate calculations and round only the final kilojoule figure to match your instrument tolerance.
More Attojoule & Kilojoule Conversions
Need to calculate in the opposite direction? Use our kilojoules to attojoules calculator to switch your starting unit immediately. You can also explore related tools such as converting kilojoules to attojoules, converting joules to kilojoules, or converting kilocalories to kilojoules.
Convert from Attojoules
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Attojoules (aJ) to Kilojoules (kJ)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Attojoule (aJ) & Kilojoule (kJ)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (aJ to kJ)