Convert BTU to therms

1 BTU=1.0000e-5thm

Use the converter below to change any BTU value into therms instantly — with formula, conversion table, and real-world examples.

You have

Equals

1.0000e-5

Conversion formula

Forward

therms = BTU × 1.0000e-5

Reverse

BTU = therms × 100,000

Example: 10 BTU × 1.0000e-5 = 1.0000e-4 thm.

About both units

From

British Thermal Unit

BTU

The British Thermal Unit equals approximately 1055 joules — the energy to raise 1 pound of water by 1 °F. Used for HVAC, heating, and air-conditioning capacity in the US. A 9000 BTU/h AC is a small room unit.

Real-world: Window AC: 5000–12,000 BTU/h. Central AC: 24,000–60,000 BTU/h. Home furnace: 60,000–100,000 BTU/h.

Read full british thermal unit reference →

Therm

thm

The therm equals 100,000 BTU or 105.5 megajoules. Used in US and UK natural-gas billing. A typical UK home uses 200–500 therms per year for heating.

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

Read full therm reference →

British Thermal Unit to Therm conversion table

Common BTU to therms values for quick reference.

British Thermal Unit (BTU)	Therm (thm)
1 BTU	1.0000e-5 thm
10 BTU	1.0000e-4 thm
100 BTU	0.001 thm
500 BTU	0.005 thm
1,000 BTU	0.01 thm
5,000 BTU	0.05 thm
10,000 BTU	0.1 thm
50,000 BTU	0.5 thm
100,000 BTU	1 thm
500,000 BTU	5 thm

Tips & common mistakes

Quick tips

1 BTU = 1055.06 J = 0.293 Wh.
BTU/h (power) and BTU (energy) are different — don't confuse.
Tons of refrigeration: 12,000 BTU/h = 1 ton AC.

Avoid these

Confusing BTU and BTU/h — energy vs power.
Using kcal when BTU is requested in HVAC specs.
Treating all BTUs as exact — definitions vary (IT, thermochemical, etc.).

Frequently asked questions

How many therms in a british thermal unit?

One british thermal unit equals 1.0000e-5 therms.

How do I convert BTU to therms?

Multiply the british thermal unit value by 1.0000e-5 to get the equivalent in therms.

What is 100 BTU in therms?

100 BTU equals 0.001 therms.

Is a british thermal unit bigger than a therm?

No. 1 british thermal unit equals 1.0000e-5 therms, so one british thermal unit is smaller.

How to convert BTU to therms without a calculator?

Multiply by 0 for a quick estimate; use a calculator for precise results.

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