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British Thermal Units to Calories Converter

Convert BTU to calories and calories to BTU instantly. Bidirectional energy converter with formula and common values.

BTU

Calories

881.986

cal

3.5 BTU = 881.986 cal

cal = BTU × 251.996

British Thermal Units to Calories: 1 BTU equals 251.996 cal. To convert british thermal units to calories, multiply by 251.996 (cal = BTU × 251.996). For example, 10 BTU = 2519.96 cal.

How to Convert British Thermal Units to Calories

To convert from british thermal units to calories, multiply the value by 251.996. The conversion is linear, meaning doubling the input doubles the output.

Conversion Formula

  • British Thermal Units to Calories: cal = BTU × 251.996
  • Calories to British Thermal Units: BTU = cal ÷ 251.996

British Thermal Units to Calories Conversion Chart

British Thermal Units (BTU)Calories (cal)
0.125.1996
0.2562.999
0.5125.998
1251.996
2503.992
3755.988
51259.98
102519.96
205039.92
256299.9
5012599.8
10025199.6
25062999
1000251996

Understanding the Units

What is a British Thermal Unit?

A British thermal unit (BTU) equals approximately 1,055.06 joules — the energy needed to raise one pound of water by one degree Fahrenheit.

Common contexts: HVAC, natural gas (US), heating systems.

What is a Calorie?

The thermochemical calorie equals exactly 4.184 joules; the historical "small" calorie raised one gram of water by one degree Celsius.

Common contexts: chemistry, historical thermodynamics.

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FAQ

How many calories are in one BTU?

One BTU equals approximately 251.996 calories (small calories). This makes BTU roughly 252 times larger than a single calorie.

How do I convert BTU to calories?

Multiply the BTU value by 251.996. For example, 3.5 BTU × 251.996 = 881.99 calories.

Are these food calories or thermochemical calories?

These are thermochemical (small) calories, not food Calories. One food Calorie (kcal) equals 1,000 small calories, so 1 BTU = about 0.252 food Calories.

Where is this conversion used?

This conversion bridges US thermal engineering (BTU) and scientific energy measurements (calories). It appears in chemistry, thermodynamics, and cross-system engineering calculations.

How many calories are in 1 british thermal unit?

1 BTU equals 251.996 cal.

How do you convert british thermal units to calories?

Multiply the british thermal unit value by 251.996. Formula: cal = BTU × 251.996.

How many calories are in 5 british thermal units?

5 BTU = 1259.98 cal.

How do you convert calories back to british thermal units?

Use the inverse formula: BTU = cal ÷ 251.996. For example, 1 cal = 0.003968 BTU.

What is the difference between British Thermal Unit and Calory?

A British thermal unit (BTU) equals approximately 1,055.06 joules — the energy needed to raise one pound of water by one degree Fahrenheit. The thermochemical calorie equals exactly 4.184 joules; the historical "small" calorie raised one gram of water by one degree Celsius.