Convert Therm to Kilojoule (thmkJ)

The therm equals 100,000 BTU and is the standard unit for natural gas billing in the US and the UK.

105,505.59
1 thm105,505.59 kJNIST · BIPM accuracy

Therm to Kilojoule Conversion Table

10 common values
ThermKilojoule
1 thm105,505.59 kJ
10 thm1,055,055.9 kJ
100 thm10,550,559 kJ
500 thm52,752,793 kJ
1,000 thm105,505,590 kJ
5,000 thm527,527,930 kJ
10,000 thm1,055,055,853 kJ
50,000 thm5,275,279,265 kJ
100,000 thm10,550,558,530 kJ
500,000 thm52,752,792,650 kJ

How to Convert Therm to Kilojoule Manually

Step by Step

Converting therms to kilojoules is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

  1. 1
    Take your value in therms
    Start with the number of therms (thm) you want to convert.
  2. 2
    Multiply by 105,505.59
    The conversion factor from thm to kJ is 105,505.59. Multiply your value by this number.
  3. 3
    Read the result in kilojoules
    The result is your value in kilojoules (kJ).
Practical Examples
1 thm
equals
105,505.59 kJ
5 thm
equals
527,527.93 kJ
10 thm
equals
1,055,055.9 kJ
25 thm
equals
2,637,639.6 kJ
100 thm
equals
10,550,559 kJ

Formula

Multiply the value in therms by 105,505.59. For the reverse direction, multiply by 0.000009478.

ForwardkJ = thm × 105,505.59
Reversethm = kJ × 0.000009478
Example: 10 thm × 105,505.59 = 1,055,055.9 kJ

Tips

Use these in everyday conversions
  • 1 therm = 100,000 BTU = 105.5 MJ = 29.3 kWh.
  • UK bills often quote both therms and kWh.
  • In metric-dominant EU, gas is billed in kWh or m³.

Common Mistakes

Avoid these
  • Comparing therms and kWh without conversion on a mixed-unit bill.
  • Assuming therms are used globally — only US and UK.
  • Using BTU when bill shows therms — factor of 100,000.

About Therm and Kilojoule

What is the Therm?

The therm equals exactly 100,000 BTU (or about 105.5 megajoules) and is the standard unit for natural-gas billing in the United States and the United Kingdom. Gas utilities deliver therms (or 'CCF' — hundred cubic feet, approximately 1 therm of natural gas). A typical US home uses 50–100 therms per month for heating in winter. The therm is also used in industrial process heating and commercial gas pricing. UK natural gas was historically sold in therms before metric conversion, and the unit persists in legacy contracts. The therm relates to the BTU (100,000 BTU = 1 therm), the megajoule (1 therm ≈ 105.5 MJ), the kilowatt-hour (1 therm ≈ 29.3 kWh), and the cubic foot of natural gas (about 100 ft³ ≈ 1 therm at standard heating value). Most metric countries bill natural gas in cubic meters or kilowatt-hours instead.

  • US residential gas bills
  • UK commercial gas billing
  • Industrial natural-gas contracts
Real-world examples

UK home heating: 200–500 therms/year. 1 therm = about $1.50 US (2024) or £1.00 UK.

What is the Kilojoule?

The kilojoule equals 1,000 joules and is the standard unit on European nutrition labels and in mid-scale chemical and physical calculations. EU regulations require food packaging to display energy in kilojoules (typically with kilocalories also shown for consumer familiarity): a chocolate bar might show '2,100 kJ / 500 kcal' per 100 g. The kilojoule is also common in chemistry (bond energies), electrical engineering (capacitor storage), and small-mechanical-energy contexts. A car battery typically stores about 1,800 kJ; lifting a person 1 meter requires roughly 0.7 kJ. The kilojoule relates to the joule (1,000 J = 1 kJ), the kilocalorie (1 kcal = 4.184 kJ), the watt-hour (1 kWh = 3,600 kJ), and the megajoule (1,000 kJ = 1 MJ). The conversion factor 4.184 (kJ per kcal) is one of the most-used numbers in nutrition labeling.

  • EU and UK nutrition labels
  • Mechanical work in engineering
  • Battery capacity in vehicles
Real-world examples

100 g chocolate: ~2100 kJ. EU daily intake (adult): ~8400 kJ. Tesla Model 3 battery: ~270 MJ = 270,000 kJ.

Learn About Both Units

Reference

What is the Therm?

Read the unit page →
Reference

What is the Kilojoule?

Read the unit page →

Therm to Kilojoule FAQ

5 questions
How many kilojoules in a therm?
One therm equals 105,505.59 kilojoules.
How do I convert therms to kilojoules?
Multiply the therm value by 105,505.59 to get the equivalent in kilojoules.
What is 100 therms in kilojoules?
100 therms equals 10,550,559 kilojoules.
Is a therm bigger than a kilojoule?
Yes. 1 therm equals 105,505.59 kilojoules, so one therm is larger.
How to convert therms to kilojoules without a calculator?
Multiply by 105,505.59 for a quick estimate; use a calculator for precise results.

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