Rydberg to Calorie (th) Converter
Convert Rydberg (Ry) to Calorie (th) (cal) instantly. 1 Ry = 5.210019e-19 cal.
Energy Converter
27 units available
1 Ry = 5.210019e-19 cal
Formula:
cal = Ry × 5.210019e-19With your value: 1 Ry = 5.210019e-19 cal
How big is that?
Everyday references on a logarithmic scale, all expressed in rydberg so you can sanity-check the result.
Other Rydberg to Calorie (th) conversions
Rydberg to Calorie (th) Conversion Table
| Rydberg (Ry) | Calorie (th) (cal) |
|---|---|
| 0.5 | 2.605010e-19 |
| 1 | 5.210019e-19 |
| 2 | 1.042004e-18 |
| 5 | 2.605010e-18 |
| 10 | 5.210019e-18 |
| 15 | 7.815029e-18 |
| 20 | 1.042004e-17 |
| 25 | 1.302505e-17 |
| 50 | 2.605010e-17 |
| 100 | 5.210019e-17 |
| 250 | 1.302505e-16 |
| 500 | 2.605010e-16 |
| 1000 | 5.210019e-16 |
Calorie (th) to Rydberg Conversion Table
| Calorie (th) (cal) | Rydberg (Ry) |
|---|---|
| 0.5 | 9.596894e+17 |
| 1 | 1.919379e+18 |
| 2 | 3.838758e+18 |
| 5 | 9.596894e+18 |
| 10 | 1.919379e+19 |
| 15 | 2.879068e+19 |
| 20 | 3.838758e+19 |
| 25 | 4.798447e+19 |
| 50 | 9.596894e+19 |
| 100 | 1.919379e+20 |
| 250 | 4.798447e+20 |
| 500 | 9.596894e+20 |
| 1000 | 1.919379e+21 |
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
Calorie (th) (cal)
Energy
The thermochemical calorie is exactly 4.184 J.
The International Table calorie (4.1868 J) and the 15 °C calorie differ slightly.
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 Calorie (th)
To convert from Rydberg (Ry) to Calorie (th) (cal), multiply the value by 5.210019e-19.
Formula: cal = Ry × 5.210019e-19
Reverse: Ry = cal × 1.919379e+18
Step-by-Step Example
- Start with your value in Rydberg. For example: 5 Ry
- Multiply by the conversion factor: 5 x 5.210019e-19
- The result is: 2.605010e-18 cal
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 Calorie (th)
The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.
Common uses: chemistry, nutrition, heating.
Frequently Asked Questions
How many Calorie (th) are in 1 Rydberg?
There are exactly 5.210019e-19 Calorie (th) in 1 Rydberg. This means the conversion factor from Rydberg to Calorie (th) is 5.210019e-19.
What is the formula to convert Rydberg to Calorie (th)?
The formula to convert Rydberg to Calorie (th) is: cal = Ry × 5.210019e-19. For example, to convert 10 Rydberg to Calorie (th), you would multiply 10 by 5.210019e-19.
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 Calorie (th)?
The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.
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 Calorie (th) converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/rydberg-to-calorie