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Energy • NIST Exact

BTUs → Joules

BTU → J

1 BTU = 1,055.0559 J• NIST Exact

BTU → J Reference Table

BTU J
0.01 BTU 10.55055853 J
0.1 BTU 105.5055853 J
0.5 BTU 527.5279263 J
1 BTU 1055.055853 J
2 BTU 2110.111705 J
5 BTU 5275.279263 J
10 BTU 10550.55853 J
20 BTU 21101.11705 J
50 BTU 52752.79263 J
100 BTU 105505.5853 J
500 BTU 527527.9263 J
1000 BTU 1055055.853 J

Values based on NIST SP 811 conversion factors

🌍 Real-World Examples

Cooling capacity of a 1-ton window AC unit

12000 BTU = 12660670.23 J

Energy in 1 therm of natural gas

100000 BTU = 105505585.3 J

Heating 1 pound of water by 1°F

1 BTU = 1055.055853 J

Hourly output of a home gas furnace

40000 BTU = 42202234.1 J

Energy equivalent of 1 kWh

3412 BTU = 3599850.569 J

Why Convert BTUs to Joules?

Converting between btus (BTU) and joules (J) is one of the most common energy conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert BTU to J saves time and prevents errors.

Energy conversions between BTU and J are important for nutrition, electricity costs, and engineering. Food labels in different countries use different energy units — China and the EU use kilojoules (kJ), while the US and Australia use Calories (kcal). Understanding kWh-to-joule conversions helps calculate electricity costs and compare energy efficiency of appliances. In HVAC, BTU ratings are standard in North America while watts or kilowatts are used elsewhere.

How to Convert BTUs to Joules

To convert btus to joules, use the following formula:

J = BTU × 1055.055853

Example: 1 BTU = 1055.055853 J

For example, 5 BTU = 5275.279263 J, 10 BTU = 10550.55853 J, and 100 BTU = 105505.5853 J. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Use Cases

  • Cooling capacity of a 1-ton window AC unit: 12000 BTU = 12660670.23 J
  • Energy in 1 therm of natural gas: 100000 BTU = 105505585.3 J
  • Heating 1 pound of water by 1°F: 1 BTU = 1055.055853 J
  • Hourly output of a home gas furnace: 40000 BTU = 42202234.1 J
  • Energy equivalent of 1 kWh: 3412 BTU = 3599850.569 J

Common Mistakes to Avoid

  • Calorie vs kilocalorie: Food labels in the US show "Calories" (capital C) which are actually kilocalories (kcal). 1 food Calorie = 1 kcal = 4.184 kJ.
  • kWh is not kW: Kilowatt-hours (kWh) measure energy consumed over time, while kilowatts (kW) measure instantaneous power. Don't confuse them.
  • Regional food labels: China/EU labels use kilojoules (kJ), US/Australia use Calories (kcal). Check which system before comparing.

Pro Tips

  • Memorize the factor: 1 BTU = 1055.055853 J. For quick mental math, remember this base conversion.
  • Quick reference: 5 BTU = 5275.279263 J · 10 BTU = 10550.55853 J · 25 BTU = 26376.39632 J · 50 BTU = 52752.79263 J · 100 BTU = 105505.5853 J
  • Bookmark this page: Save this converter for instant access. It works offline once loaded — no internet needed.

BTUs to Joules Conversion Table

BTUJ
0.01 BTU10.55055853 J
0.1 BTU105.5055853 J
0.5 BTU527.5279263 J
1 BTU1055.055853 J
2 BTU2110.111705 J
5 BTU5275.279263 J
10 BTU10550.55853 J
20 BTU21101.11705 J
50 BTU52752.79263 J
100 BTU105505.5853 J
500 BTU527527.9263 J
1000 BTU1055055.853 J

All values in this table are mathematically exact per NIST SP 811.

Frequently Asked Questions

How many joules are in 1 btu?

1 BTU equals 1055.055853 J. This is an exact conversion factor defined by NIST.

How do I convert btus to joules?

Multiply the value in BTU by the conversion factor. For example, 10 BTU = 10550.55853 J. Use our calculator above for instant results.

Is the btus to joules conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

Energy More Conversions

kJ → kcal kcal → kJ J → cal cal → J kWh → J