A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
Millijoules to Btu
Convert Millijoule (mJ) to British thermal unit (BTU) instantly with an exact formula, conversion table, and FAQ.
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Convert millijoules (mJ) to btu (BTU) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings.
BTU = mJ × 9.478171203e-07
Results update instantly for Millijoules to Btu conversions.
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Formula
BTU = mJ × 9.478171203e-07
mJ = BTU × 1055055.853
Conversion table
| 1 mJ | 9.478171e-07 BTU |
| 5 mJ | 0.000005 BTU |
| 10 mJ | 0.000009 BTU |
| 20 mJ | 0.000019 BTU |
| 50 mJ | 0.000047 BTU |
| 100 mJ | 0.000095 BTU |
| 500 mJ | 0.000474 BTU |
| 1000 mJ | 0.000948 BTU |
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How the formula works
Both millijoule and british thermal unit measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in millijoules by 9.478171203e-07 to get btu. To reverse the conversion, multiply a british thermal unit value by 1055055.853 to get back to millijoules.
Frequently asked questions
What is Millijoule (mJ)?
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
What is British thermal unit (BTU)?
The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings.
How do I convert millijoules to btu?
Multiply the millijoule value by 9.478171203e-07 to get the equivalent in btu. For example, 5 mJ × 9.478171203e-07 = 0.000005 BTU.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 9.478171203e-07 is an exact, non-rounded value.
Can I convert btu back to millijoules?
Yes. Divide the british thermal unit value by 9.478171203e-07, or multiply it by 1055055.853, to get millijoules.
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About converting millijoules to btu
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix. The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings.
Use this calculator to move between millijoules and btu accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.