How many BTU is 1000 cal?

1000 ÷ 252.164 = 3.966 BTU. A small candle produces about 80 BTU/h.

A furnace is 50,000 BTU — how many cal?

50,000 × 252.164 = 12,608,200 cal/h. Typical residential furnace.

Why divide by 252.164?

1 BTU = 1055.056 J = 1055.056/4.184 = 252.164 cal. To get BTU from cal, divide by 252.164.

Is 1 cal exactly 1/252.164 BTU?

1 cal (thermochemical) = 4.184 J, 1 BTU (IT) = 1055.056 J, so 1 cal = 4.184/1055.056 BTU. See [Calories to Joules](/energy/calories-to-joules/) for the SI foundation.

Calories (cal) to BTU (IT) Converter

Enter a value to instantly convert between energy units.

From

Precision4 dp

1 Calorie (thermochemical) = 0.004 BTU (IT)

Key Formulas

Kilocalorie → Kilojoule

kJ = kcal × 4.184

Kilojoule → Kilocalorie

kcal = kJ × 0.239006

Kilowatt-Hour → Joule

J = kWh × 3600000

Joule → Kilowatt-Hour

kWh = J × 2.77778e-7

Formula

BTU = cal ÷ 252.164

One BTU (IT) equals approximately 252 thermochemical calories. Since 1 BTU = 1.055 J and 1 cal = 4.184 J, the conversion is 1 cal = 1/252.164 BTU. This is used in US HVAC calculations, furnace ratings, and heating equipment specs.

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

An HVAC technician learning that 252 cal equals 1 BTU for the equipment manual.

252.164 cal = 1 BTU

A heating engineer calculating 1000 cal from a burner reports 3.97 BTU for the analysis.

1000 cal = 3.966 BTU

A food scientist analyzing 500 cal of energy in a serving converts to 1.98 BTU for the comparison.

500 cal = 1.983 BTU

A furnace producing 10,000 cal of heat per minute delivers 39.66 BTU/min for the spec.

10000 cal = 39.66 BTU

kcal to kj kj to kcal kwh to joules joules to kwh btu to joules calories to joules

Calories (cal) to BTU (IT) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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