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    Track joules, calories, BTU, and kWh in the same dashboard.

    Energy Conversion Guide

    Energy units appear in fitness trackers, electrical billing, and industrial heating. This guide keeps the relationships clear so you can reconcile reports in any system.

    Because energy spans mechanical work and heat, legacy and modern units coexist. Use the table to relate them all back to the joule, then cross-check the most common conversions for your domain.

    Base unit

    Joule (J)

    Units covered

    6

    Popular conversions

    2

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    30 options
    J → calJoule to CalorieView detailsJ → kJJoule to KilojouleView detailsJ → BTUJoule to British Thermal UnitView detailsJ → kcalJoule to Kilocalorie (food)View detailsJ → kWhJoule to Kilowatt HourView detailscal → JCalorie to JouleView detailscal → kJCalorie to KilojouleView detailscal → BTUCalorie to British Thermal UnitView detailscal → kcalCalorie to Kilocalorie (food)View detailscal → kWhCalorie to Kilowatt HourView detailskJ → JKilojoule to JouleView detailskJ → calKilojoule to CalorieView detailskJ → BTUKilojoule to British Thermal UnitView detailskJ → kcalKilojoule to Kilocalorie (food)View detailskJ → kWhKilojoule to Kilowatt HourView detailsBTU → JBritish Thermal Unit to JouleView detailsBTU → calBritish Thermal Unit to CalorieView detailsBTU → kJBritish Thermal Unit to KilojouleView detailsBTU → kcalBritish Thermal Unit to Kilocalorie (food)View detailsBTU → kWhBritish Thermal Unit to Kilowatt HourView detailskcal → JKilocalorie (food) to JouleView detailskcal → calKilocalorie (food) to CalorieView detailskcal → kJKilocalorie (food) to KilojouleView detailskcal → BTUKilocalorie (food) to British Thermal UnitView detailskcal → kWhKilocalorie (food) to Kilowatt HourView detailskWh → JKilowatt Hour to JouleView detailskWh → calKilowatt Hour to CalorieView detailskWh → kJKilowatt Hour to KilojouleView detailskWh → BTUKilowatt Hour to British Thermal UnitView detailskWh → kcalKilowatt Hour to Kilocalorie (food)View details

    Unit breakdown

    Every unit below references the SI base value so you can compare readings quickly.

    UnitSymbol1 unit in JNotes
    JouleJReference unit—
    Caloriecal1 cal = 4.184 J—
    KilojoulekJ1 kJ = 1K J—
    British Thermal UnitBTU1 BTU = 1.06K J—
    Kilocalorie (food)kcal1 kcal = 4.18K J—
    Kilowatt HourkWh1 kWh = 3.6000×10^+6 J—

    Popular conversions

    These presets mirror the quick actions available inside the SwapUnits converter.

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    ConversionExampleReference pageWhy it matters
    Kilowatt Hours to BTU1 kWh = 3.41K BTUOpenIdeal for quick checks inside the live converter.
    Joules to Calories1 J = 0.239006 calOpenIdeal for quick checks inside the live converter.

    Frequently asked questions

    Why do nutrition labels use Calories with a capital C?

    A nutrition “Calorie” is a kilocalorie—the energy needed to raise 1 kilogram of water by 1 °C. Scientists often write kcal, while consumer packaging simplifies it to Calorie.

    How many BTU are in a kilowatt-hour?

    One kilowatt-hour equals roughly 3,412 BTU. HVAC designers use this conversion when comparing electric and gas heating efficiency.

    Is a joule the same as a newton-meter?

    Yes. One joule equals the work done by one newton of force acting through one meter. It is the SI unit for energy.

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