Skip to main content
    UnitConvertLab
    UnitConvertLAB
    Energy Conversion

    Calorie (th) to BTU (th) Converter

    Quick answer

    To convert Calorie (th)s to BTU (th)s, multiply by 0.0039683217 (or divide by 251.9956978967). Therefore, 1 Calorie (th) (cal) equals 0.00396832 BTU (th)s (BTU).

    Formula: BTU = cal × 0.0039683217. Worked example: 10 cal = 0.039683 BTU.

    Convert Calorie (th) (cal) to BTU (th) (BTU) online with our free unit converter. In energy, 1 cal = 0.003968 BTU. Explore step-by-step conversion steps, mathematical formulas, and quick conversion reference tables below.

    Worked example: converting Calorie (th) to BTU (th)

    1. Step 1 — start with the formula. BTU = cal × 0.0039683217
    2. Step 2 — substitute your figure. 10 cal × 0.0039683217
    3. Step 3 — read the result. 10 cal = 0.039683 BTU
    4. Step 4 — check it in reverse. cal = BTU × 251.9956978967 returns 9.9999 cal, which matches the figure you started with.

    Energy Converter

    27 units available

    Decimals:
    0.003968

    1 cal = 0.003968 BTU

    Formula:

    BTU = cal × 0.0039683217

    With your value: 1 cal = 0.00396832 BTU

    How big is that?

    Everyday references on a logarithmic scale, all expressed in calorie (th) so you can sanity-check the result.

    Heartbeat (1/4.2 your value)0.239 cal
    Your value1.00 cal
    AA battery charge (2.4e+3× your value)2.39e+3 cal
    Slice of bread (6.7e+4× your value)6.69e+4 cal
    Daily food intake (2.0e+6× your value)2.01e+6 cal
    Litre of petrol (8.2e+6× your value)8.17e+6 cal

    Other Calorie (th) to BTU (th) conversions

    2 cal to BTU3 cal to BTU4 cal to BTU5 cal to BTU6 cal to BTU7 cal to BTU8 cal to BTU

    Calorie (th) to BTU (th) Conversion Table

    Calorie (th) (cal)BTU (th) (BTU)
    0.50.001984
    10.003968
    20.007937
    50.019842
    100.039683
    150.059525
    200.079366
    250.099208
    500.198416
    1000.396832
    2500.99208
    5001.984161
    10003.968322

    BTU (th) to Calorie (th) Conversion Table

    BTU (th) (BTU)Calorie (th) (cal)
    0.5125.997849
    1251.995698
    2503.991396
    51,259.978489
    102,519.956979
    153,779.935468
    205,039.913958
    256,299.892447
    5012,599.784895
    10025,199.56979
    25062,998.924474
    500125,997.848948
    1000251,995.697897

    Where these values come from

    Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

    Calorie (th) (cal)

    Energy

    Exact conversion

    The thermochemical calorie is exactly 4.184 J.

    The International Table calorie (4.1868 J) and the 15 °C calorie differ slightly.

    Source: NIST Special Publication 811, Guide for the Use of the International System of Units

    National Institute of Standards and Technology (US) · Reviewed 2026-07-01

    BTU (th) (BTU)

    Energy

    Exact conversion

    The International Table BTU is exactly 1055.055 852 62 J.

    Thermochemical and 39 °F BTU definitions differ by up to 0.2 %.

    Source: NIST Special Publication 811, Guide for the Use of the International System of Units

    National Institute of Standards and Technology (US) · Reviewed 2026-07-01

    How to Convert Calorie (th) to BTU (th)

    To convert from Calorie (th) (cal) to BTU (th) (BTU), multiply the value by 0.0039683217.

    Formula: BTU = cal × 0.0039683217

    Reverse: cal = BTU × 251.9956978967

    Step-by-Step Example

    1. Start with your value in Calorie (th). For example: 5 cal
    2. Multiply by the conversion factor: 5 x 0.0039683217
    3. The result is: 0.019842 BTU

    Calorie (th) and BTU (th) Relationship

    This calculation facilitates standardized conversion between recognized units of energy. Since 1 Calorie (th) represents a fraction of a BTU (th) (1 BTU (th) ≈ 251.9957 Calorie (th)s), the BTU (th) is the larger measurement interval. Understanding the relationship between Calorie (th) and BTU (th) is essential for accurate calculations in physics, engineering, commerce, and daily applications.

    About Calorie (th)

    The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.

    Common uses of Calorie (th): chemistry, nutrition, heating.

    About BTU (th)

    The BTU (th) (symbol: BTU) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.

    Common uses of BTU (th): energy calculations, engineering and science, education.

    Frequently Asked Questions

    How many BTU (th)s are in 1 Calorie (th)?
    There are exactly 0.0039683217 BTU (th)s in 1 Calorie (th). This means the conversion factor from Calorie (th) to BTU (th) is 0.0039683217.
    What is the formula to convert Calorie (th) to BTU (th)?
    The formula to convert Calorie (th) to BTU (th) is: BTU = cal × 0.0039683217. For example, to convert 10 Calorie (th)s to BTU (th)s, you would multiply 10 by 0.0039683217.
    What is a Calorie (th)?
    The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.
    What is a BTU (th)?
    The BTU (th) (symbol: BTU) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.
    What are the common uses of Calorie (th)?
    The Calorie (th) is commonly used in chemistry, nutrition, heating.

    Related Energy Conversions

    Joule → BTU (th)Kilojoule → BTU (th)Megajoule → BTU (th)Gigajoule → BTU (th)Millijoule → BTU (th)Calorie (th) → JouleCalorie (th) → KilojouleCalorie (th) → MegajouleCalorie (th) → Gigajoule

    Cite this page

    UnitConvertLab. (2026). Calorie (th) to BTU (th) converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/calorie-to-btu