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Energy Converter
The most comprehensive energy conversion tool available. Convert between 60+ units including Joules, kWh, Calories, BTU, Electronvolts, and Fuel Equivalents with scientific precision.
Energy Conversion Interface
Converted Result
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Math:
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Electrical Context
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Nutritional Equivalent
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Physical Work
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About
Energy is the fundamental currency of the universe, yet its accounting is fragmented across dozens of disciplines. Physicists calculate atomic transitions in Electronvolts (eV), nutritionists measure metabolic intake in Kilocalories (kcal), and engineers manage power grids using Terawatt-hours (TWh). Inaccurate conversion between these scales - differing by orders of magnitude - can lead to catastrophic engineering failures or critical data misinterpretation.
This tool bridges these distinct scientific silos. It normalizes over 60 distinct energy units into a base Joule standard before projecting them to the target unit. This "Base-Joule Architecture" ensures floating-point precision is maintained whether you are calculating the sub-atomic energy of a photon or the explosive yield of a supernova. We strictly distinguish between thermochemical definitions (e.g., BTUth vs BTUISO) to satisfy rigorous engineering standards.
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joules to calories
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Formulas
All conversions utilize a linear transformation through the SI derived unit, the Joule. To convert from an input unit u1 to a target unit u2, we use their specific energy constants k1 and k2:
Etarget = Einput × k1k2
For example, converting Kilowatt-hours to BTUIT involves expanding the time component of power and normalizing for thermal equivalency:
1 kWh = 3.6 × 106 J × 1 BTU1055.05585 J ≈ 3412.14 BTU
Reference Data
| Unit | Symbol | Exact Value (Joules) | Primary Use Case |
|---|---|---|---|
| Planck Energy | Ep | 1.956 × 109 | Quantum Gravity, Big Bang Cosmology |
| Hartree | Eh | 4.359 × 10-18 | Atomic Physics, Quantum Chemistry |
| Electronvolt | eV | 1.602 × 10-19 | Particle Accelerators, Semiconductor Physics |
| Thermochemical Calorie | calth | 4.184 | Chemistry, Thermodynamics |
| International Steam Table Calorie | calIT | 4.1868 | Steam Engineering |
| British Thermal Unit (ISO) | BTUISO | 1055.056 | HVAC, Heating Systems |
| Watt-hour | Wh | 3600 | Consumer Electronics Batteries |
| Kilowatt-hour | kWh | 3.6 × 106 | Residential Electricity Billing |
| Ton of TNT | tTNT | 4.184 × 109 | Seismology, Explosive Yields |
| Barrel of Oil Equivalent | BOE | ≈ 6.12 × 109 | Petroleum Industry, Economics |
| Quad | quad | 1.055 × 1018 | National Energy Policy, Global Statistics |
Frequently Asked Questions
Historical definitions relied on experimental conditions. A "calorie" was the energy to heat water by 1°C, but the energy required changes depending on the starting temperature (e.g., 15°C vs 20°C). This led to variants like the "Mean Calorie", "4°C Calorie", and "Thermochemical Calorie". In modern engineering, we use standardized exact definitions (ISO or International Table) to avoid ambiguity.
Energy (Joules, kWh) is the capacity to do work. Power (Watts, Horsepower) is the rate at which energy is used. For example, a 100-Watt lightbulb uses energy at a rate of 100 Joules per second. In one hour, it consumes 100 Watt-hours (energy).
You cannot convert milliampere-hours (mAh) to Watt-hours (Wh) without knowing the voltage. The formula is: Wh = (mAh × Voltage) / 1000. For a standard 3.7V lithium phone battery with 3000mAh, the energy is (3000 × 3.7) / 1000 = 11.1 Wh.
Yes. We include the "Kilogram (Mass Energy)" unit. Based on E=mc², 1 kg of matter contains approximately 9 × 10^16 Joules of intrinsic energy, a conversion often used in nuclear physics.
Scientific notation is automatic when values exceed standard display limits (too large or too small). "1.5e+6" implies 1.5 × 10^6, or 1,500,000. This ensures precision is not lost in a long string of zeros.