Rydberg to Kilojoule Converter

Energy Converter

27 units available

Decimals:

From

To

2.179872e-21

1 Ry = 2.179872e-21 kJ

Formula:

kJ = Ry × 2.179872e-21

With your value: 1 Ry = 2.179872e-21 kJ

How big is that?

Everyday references on a logarithmic scale, all expressed in rydberg so you can sanity-check the result.

Your value1.00 Ry

Heartbeat (4.6e+17× your value)4.59e+17 Ry

AA battery charge (4.6e+21× your value)4.59e+21 Ry

Slice of bread (1.3e+23× your value)1.28e+23 Ry

Daily food intake (3.9e+24× your value)3.85e+24 Ry

Litre of petrol (1.6e+25× your value)1.57e+25 Ry

Other Rydberg to Kilojoule conversions

2 Ry to kJ 3 Ry to kJ 4 Ry to kJ 5 Ry to kJ 6 Ry to kJ 7 Ry to kJ 8 Ry to kJ

Rydberg to Kilojoule Conversion Table

Rydberg (Ry)	Kilojoule (kJ)
0.5	1.089936e-21
1	2.179872e-21
2	4.359744e-21
5	1.089936e-20
10	2.179872e-20
15	3.269808e-20
20	4.359744e-20
25	5.449680e-20
50	1.089936e-19
100	2.179872e-19
250	5.449680e-19
500	1.089936e-18
1000	2.179872e-18

Kilojoule to Rydberg Conversion Table

Kilojoule (kJ)	Rydberg (Ry)
0.5	2.293713e+20
1	4.587425e+20
2	9.174851e+20
5	2.293713e+21
10	4.587425e+21
15	6.881138e+21
20	9.174851e+21
25	1.146856e+22
50	2.293713e+22
100	4.587425e+22
250	1.146856e+23
500	2.293713e+23
1000	4.587425e+23

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

Exact conversion

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

Kilojoule (kJ)

Energy

Exact conversion

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 Kilojoule

To convert from Rydberg (Ry) to Kilojoule (kJ), multiply the value by 2.179872e-21.

Formula: kJ = Ry × 2.179872e-21

Reverse: Ry = kJ × 4.587425e+20

Step-by-Step Example

Start with your value in Rydberg. For example: 5 Ry
Multiply by the conversion factor: 5 x 2.179872e-21
The result is: 1.089936e-20 kJ

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 Kilojoule

The kilojoule (kJ) is a unit of energy and work. One kilojoule equals 1000 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.

Frequently Asked Questions

How many Kilojoule are in 1 Rydberg?

There are exactly 2.179872e-21 Kilojoule in 1 Rydberg. This means the conversion factor from Rydberg to Kilojoule is 2.179872e-21.

What is the formula to convert Rydberg to Kilojoule?

The formula to convert Rydberg to Kilojoule is: kJ = Ry × 2.179872e-21. For example, to convert 10 Rydberg to Kilojoule, you would multiply 10 by 2.179872e-21.

What is a Rydberg?