Hartree to Kilocalorie Converter

Energy Converter

27 units available

Decimals:

From

To

1.042004e-21

1 Eh = 1.042004e-21 kcal

Formula:

kcal = Eh × 1.042004e-21

With your value: 1 Eh = 1.042004e-21 kcal

How big is that?

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

Your value1.00 Eh

Heartbeat (2.3e+17× your value)2.29e+17 Eh

AA battery charge (2.3e+21× your value)2.29e+21 Eh

Slice of bread (6.4e+22× your value)6.42e+22 Eh

Daily food intake (1.9e+24× your value)1.93e+24 Eh

Litre of petrol (7.8e+24× your value)7.84e+24 Eh

Other Hartree to Kilocalorie conversions

2 Eh to kcal 3 Eh to kcal 4 Eh to kcal 5 Eh to kcal 6 Eh to kcal 7 Eh to kcal 8 Eh to kcal

Hartree to Kilocalorie Conversion Table

Hartree (Eh)	Kilocalorie (kcal)
0.5	5.210020e-22
1	1.042004e-21
2	2.084008e-21
5	5.210020e-21
10	1.042004e-20
15	1.563006e-20
20	2.084008e-20
25	2.605010e-20
50	5.210020e-20
100	1.042004e-19
250	2.605010e-19
500	5.210020e-19
1000	1.042004e-18

Kilocalorie to Hartree Conversion Table

Kilocalorie (kcal)	Hartree (Eh)
0.5	4.798446e+20
1	9.596892e+20
2	1.919378e+21
5	4.798446e+21
10	9.596892e+21
15	1.439534e+22
20	1.919378e+22
25	2.399223e+22
50	4.798446e+22
100	9.596892e+22
250	2.399223e+23
500	4.798446e+23
1000	9.596892e+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.

Hartree (Eh)

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

Kilocalorie (kcal)

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 Hartree to Kilocalorie

To convert from Hartree (Eh) to Kilocalorie (kcal), multiply the value by 1.042004e-21.

Formula: kcal = Eh × 1.042004e-21

Reverse: Eh = kcal × 9.596892e+20

Step-by-Step Example

Start with your value in Hartree. For example: 5 Eh
Multiply by the conversion factor: 5 x 1.042004e-21
The result is: 5.210020e-21 kcal

About Hartree

The hartree (Eh) is a unit of energy and work. One hartree equals 4.359745 × 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 Kilocalorie

The kilocalorie (food Calorie) equals 1,000 calories or 4,184 joules. It is the standard unit for food energy content.

Common uses: nutrition, diet, food labeling.

Frequently Asked Questions

How many Kilocalorie are in 1 Hartree?

There are exactly 1.042004e-21 Kilocalorie in 1 Hartree. This means the conversion factor from Hartree to Kilocalorie is 1.042004e-21.

What is the formula to convert Hartree to Kilocalorie?

The formula to convert Hartree to Kilocalorie is: kcal = Eh × 1.042004e-21. For example, to convert 10 Hartree to Kilocalorie, you would multiply 10 by 1.042004e-21.

What is a Hartree?