Horsepower-Hour to Millijoule Converter

Energy Converter

27 units available

Decimals:

From

To

2,684,519,537.700001

1 hp·h = 2,684,519,537.700001 mJ

Formula:

mJ = hp·h × 2.684520e+9

With your value: 1 hp·h = 2,684,519,537.7000003 mJ

How big is that?

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

Heartbeat (1/2.7e+6 your value)3.73e-7 hp·h

AA battery charge (1/2.7e+2 your value)0.00373 hp·h

Slice of bread (1/9.6 your value)0.104 hp·h

Your value1.00 hp·h

Daily food intake (3.1× your value)3.13 hp·h

Litre of petrol (13× your value)12.7 hp·h

Other Horsepower-Hour to Millijoule conversions

2 hp·h to mJ 3 hp·h to mJ 4 hp·h to mJ 5 hp·h to mJ 6 hp·h to mJ 7 hp·h to mJ 8 hp·h to mJ

Horsepower-Hour to Millijoule Conversion Table

Horsepower-Hour (hp·h)	Millijoule (mJ)
0.5	1,342,259,768.85
1	2,684,519,537.700001
2	5,369,039,075.400001
5	13,422,597,688.500002
10	26,845,195,377.000004
15	40,267,793,065.50001
20	53,690,390,754.00001
25	67,112,988,442.50001
50	134,225,976,885.00002
100	268,451,953,770.00003
250	671,129,884,425.0001
500	1.342260e+12
1000	2.684520e+12

Millijoule to Horsepower-Hour Conversion Table

Millijoule (mJ)	Horsepower-Hour (hp·h)
0.5	1.862531e-10
1	3.725061e-10
2	7.450123e-10
5	1.862531e-9
10	3.725061e-9
15	5.587592e-9
20	7.450123e-9
25	9.312653e-9
50	1.862531e-8
100	3.725061e-8
250	9.312653e-8
500	1.862531e-7
1000	3.725061e-7

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.

Horsepower-Hour (hp·h)

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

Millijoule (mJ)

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 Horsepower-Hour to Millijoule

To convert from Horsepower-Hour (hp·h) to Millijoule (mJ), multiply the value by 2,684,519,537.7000003.

Formula: mJ = hp·h × 2.684520e+9

Reverse: hp·h = mJ × 3.725061e-10

Step-by-Step Example

Start with your value in Horsepower-Hour. For example: 5 hp·h
Multiply by the conversion factor: 5 x 2,684,519,537.7000003
The result is: 13,422,597,688.500002 mJ

About Horsepower-Hour

The horsepower-hour (hp·h) is a unit of energy and work. One horsepower-hour equals 2.684520 × 10^+6 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 Millijoule

The millijoule (mJ) is a unit of energy and work. One millijoule equals 0.001 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 Millijoule are in 1 Horsepower-Hour?

There are exactly 2,684,519,537.7000003 Millijoule in 1 Horsepower-Hour. This means the conversion factor from Horsepower-Hour to Millijoule is 2,684,519,537.7000003.

What is the formula to convert Horsepower-Hour to Millijoule?

The formula to convert Horsepower-Hour to Millijoule is: mJ = hp·h × 2.684520e+9. For example, to convert 10 Horsepower-Hour to Millijoule, you would multiply 10 by 2,684,519,537.7000003.

What is a Horsepower-Hour?