Convert BTU to calories

1 BTU=252.164cal

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

You have

Equals

252.1644

Conversion formula

Forward

calories = BTU × 252.164

Reverse

BTU = calories × 0.003966

Example: 10 BTU × 252.164 = 2,521.64 cal.

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 →

Calorie

cal

The gram calorie (small calorie) equals 4.184 joules — the energy to raise 1 g of water by 1 °C. It is a scientific unit, distinct from the nutrition "Calorie" (kcal). Largely replaced by joules in modern science.

Real-world: Raising 1 g of water 1 °C: 1 cal. A 100 kcal snack = 100,000 small calories.

Read full calorie reference →

British Thermal Unit to Calorie conversion table

Common BTU to calories values for quick reference.

British Thermal Unit (BTU)	Calorie (cal)
1 BTU	252.164 cal
10 BTU	2,521.64 cal
100 BTU	25,216.44 cal
500 BTU	126,082.2 cal
1,000 BTU	252,164.4 cal
5,000 BTU	1,260,822 cal
10,000 BTU	2,521,644 cal
50,000 BTU	12,608,220 cal
100,000 BTU	25,216,440.01 cal
500,000 BTU	126,082,200.05 cal

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 calories in a british thermal unit?

One british thermal unit equals 252.164 calories.

How do I convert BTU to calories?

Multiply the british thermal unit value by 252.164 to get the equivalent in calories.

What is 100 BTU in calories?

100 BTU equals 25,216.44 calories.

Is a british thermal unit bigger than a calorie?

Yes. 1 british thermal unit equals 252.164 calories, so one british thermal unit is larger.

How to convert BTU to calories without a calculator?

Multiply by 252.16 for a quick estimate; use a calculator for precise results.

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