How do I convert cal to BTU?

Use the formula shown above or enter a value to see cal converted to BTU instantly.

What is the formula for cal to BTU?

The converter calculates BTU by applying the category-specific conversion factor for Energy.

When should I use cal vs BTU?

cal and BTU are both part of the Energy category; pick the unit that matches your measurement context (e.g., scale, region, or industry standard).

Energy Conversion Guide

Convert cal to BTU

Use the live converter below to translate between Calorie (cal) and British Thermal Unit (BTU). Scroll further for quick examples, formula tips, and related units.

Formula insight: Most unit conversions use a simple multiplication or division by a conversion factor. The calculator shows the exact formula used.

Convert

cal → BTU

Calorie

cal

British Thermal Unit

0.004

BTU

Rounded result (4 decimals max)

Formula

1 cal = 0.004 BTU

Conversion sourcesTap or click to view references

The International System of Units (SI) — NIST Special Publication 330
National Institute of Standards and Technology (NIST). The SI Brochure (SP 330) is the definitive English edition of the BIPM SI tables. NIST’s edition lists the official constants and conversion factors tying inch-pound units to SI, which SwapUnits applies for length, mass, temperature, pressure, volume, and related conversions. See /standards/nist-si-tenfold for the complete decimal multiple/submultiple table. View source · View SI table

Results update as you type. Swap the direction to convert back from BTU to cal.

Back to main converter

cal to BTU quick table

Multiply any row by the same factor to scale results. Use the converter above to enter exact values with your own units.

Calorie (cal)	British Thermal Unit (BTU)
0.25 cal	0.001 BTU
0.5 cal	0.002 BTU
1 cal	0.004 BTU
2 cal	0.0079 BTU
5 cal	0.0198 BTU
10 cal	0.0397 BTU
25 cal	0.0991 BTU
100 cal	0.3966 BTU

BTU back to cal

Keep the reciprocal handy when double-checking calculations or undoing a conversion.

British Thermal Unit (BTU)	Calorie (cal)
0.25 BTU	63.0411 cal
0.5 BTU	126.0822 cal
1 BTU	252.1644 cal
2 BTU	504.3288 cal
5 BTU	1,260.822 cal
10 BTU	2,521.644 cal
25 BTU	6,304.11 cal
100 BTU	25,216.4401 cal

Explore more energy conversion guide

cal → J

Convert into Joule without leaving SwapUnits.

cal → kJ

Convert into Kilojoule without leaving SwapUnits.

cal → kcal

Convert into Kilocalorie (food) without leaving SwapUnits.

cal → kWh

Convert into Kilowatt Hour without leaving SwapUnits.

Compare all energy conversion guide

View the full unit roster, charts, and tips for Energy Conversion Guide conversions.

Open category guide