Rydberg to Joule Converter
Convert Rydberg (Ry) to Joule (J) instantly. 1 Ry = 2.179872e-18 J.
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27 units available
1 Ry = 2.179872e-18 J
Formula:
J = Ry × 2.179872e-18With your value: 1 Ry = 2.179872e-18 J
How big is that?
Everyday references on a logarithmic scale, all expressed in rydberg so you can sanity-check the result.
Other Rydberg to Joule conversions
Rydberg to Joule Conversion Table
| Rydberg (Ry) | Joule (J) |
|---|---|
| 0.5 | 1.089936e-18 |
| 1 | 2.179872e-18 |
| 2 | 4.359744e-18 |
| 5 | 1.089936e-17 |
| 10 | 2.179872e-17 |
| 15 | 3.269808e-17 |
| 20 | 4.359744e-17 |
| 25 | 5.449680e-17 |
| 50 | 1.089936e-16 |
| 100 | 2.179872e-16 |
| 250 | 5.449680e-16 |
| 500 | 1.089936e-15 |
| 1000 | 2.179872e-15 |
Joule to Rydberg Conversion Table
| Joule (J) | Rydberg (Ry) |
|---|---|
| 0.5 | 2.293713e+17 |
| 1 | 4.587425e+17 |
| 2 | 9.174851e+17 |
| 5 | 2.293713e+18 |
| 10 | 4.587425e+18 |
| 15 | 6.881138e+18 |
| 20 | 9.174851e+18 |
| 25 | 1.146856e+19 |
| 50 | 2.293713e+19 |
| 100 | 4.587425e+19 |
| 250 | 1.146856e+20 |
| 500 | 2.293713e+20 |
| 1000 | 4.587425e+20 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Rydberg (Ry)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
Joule (J)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
How to Convert Rydberg to Joule
To convert from Rydberg (Ry) to Joule (J), multiply the value by 2.179872e-18.
Formula: J = Ry × 2.179872e-18
Reverse: Ry = J × 4.587425e+17
Step-by-Step Example
- Start with your value in Rydberg. For example: 5 Ry
- Multiply by the conversion factor: 5 x 2.179872e-18
- The result is: 1.089936e-17 J
About Rydberg
The rydberg (Ry) is a unit of energy and work. One rydberg equals 2.179872 × 10^-18 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: energy calculations, engineering and science, education.
About Joule
The joule is the SI unit of energy. One joule equals the work done when a force of one newton moves an object one meter.
Common uses: physics, electrical engineering, chemistry.
Frequently Asked Questions
How many Joule are in 1 Rydberg?
There are exactly 2.179872e-18 Joule in 1 Rydberg. This means the conversion factor from Rydberg to Joule is 2.179872e-18.
What is the formula to convert Rydberg to Joule?
The formula to convert Rydberg to Joule is: J = Ry × 2.179872e-18. For example, to convert 10 Rydberg to Joule, you would multiply 10 by 2.179872e-18.
What is a Rydberg?
The rydberg (Ry) is a unit of energy and work. One rydberg equals 2.179872 × 10^-18 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What is a Joule?
The joule is the SI unit of energy. One joule equals the work done when a force of one newton moves an object one meter.
What are the common uses of Rydberg?
The Rydberg is commonly used in energy calculations, engineering and science, education.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Rydberg to Joule converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/rydberg-to-joule