How do I convert Calorie (cal) to BTU (IT)?

1 cal equals 0.003966 btu using SI-based conversion and precise factors.

What is the formula to convert Calorie (cal) to BTU (IT)?

This is a linear unit conversion using a constant factor between units.

Yes, it uses exact definitions or standardized constants (e.g., 1 in = 25.4 mm).

Use the shareable URL pattern: /convert/cal-to-btu/1

Category: Energy

Value From To Precision

0.003966 btu

1 cal = 0.003966 btu

High-precision rounding: 6 decimals

We convert by pivoting through the SI base unit for Energy and applying exact factors where applicable.

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Energy is capacity to do work; joules, calories, Wh and BTU are common.

Calorie (cal)

Energy to heat 1 g of water by 1 °C (various defs).

History: Historical thermochemistry unit; 1 cal ≈ 4.184 J.

British thermal unit (BTU)

≈ 1,055.06 J (IT).

History: Steam age heat unit; HVAC standard.