Convert Energy Units
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📘 Overview: Instantly Convert Between Energy Units
Energy appears in various forms across disciplines — from the food we eat to the electricity we consume, the fuel we burn, and the particles we accelerate. This tool allows you to instantly convert between dozens of energy units including:
- Joule (J) – SI base unit of energy
- Calorie (Cal) – Food energy (1 Cal = 4184 J)
- BTU – Heating and cooling energy in HVAC
- kW·h – Electricity billing (kilowatt-hour)
- Electronvolt (eV) – Energy at subatomic scale
- Barrel of oil equivalent (boe) – Energy in fuel industry
- Therm – Natural gas consumption
- Foot-pound force (ft·lbf) – Mechanical work
Toggle Advanced Mode to unlock over 20 additional specialized units including CHUIT, scf, thermie, toe, ton of TNT, quad, and Rydberg.
📐 Formula & Methodology
All conversions are routed through the SI base unit joule (J) for precision. The conversion follows this two-step approach:
E(J) = Input × factor_from Result = E(J) ÷ factor_to
For example, to convert 10 kW·h to joules: 10 × 3.6×10⁶ = 36,000,000 J
📊 Sample Conversion Table (Unit → Joules)
| Unit | Symbol | → J | Note |
|---|---|---|---|
| Joule | J | 1 | SI base unit |
| Kilowatt-hour | kW·h | 3.6×10⁶ | Electricity billing unit |
| Calorie | Cal | 4184 | Food-energy unit (kcal) |
| BTU | BTU | 1055.056 | Heating/cooling |
| Electronvolt | eV | 1.602×10⁻¹⁹ | Particle physics |
| Celsius heat unit | CHUIT | 4184 | Same as 1 dietary Calorie |
| Standard cm³ atm | cc atm | 101325 × 10⁻⁶ | 1 cm³ of air at STP |
| Standard ft³ atm | scf | 101325 × 0.0283168 | 1 ft³ of air at STP |
| Standard yd³ atm | scy | 101325 × 0.764555 | 1 yd³ of air at STP |
| Foot-pound force | ft·lbf | 1.3558179 | Mechanical work |
| Foot-poundal | ft·pdl | 0.04214 | CGS mechanical |
| Imp gal atm | imp gal atm | 101325 × 0.0045461 | Imperial gallon of air at STP |
| US gal atm | US gal atm | 101325 × 0.00378541 | US gallon of air at STP |
| Hartree | Eh | 4.359744e-18 | Atomic unit of energy |
| Erg | erg | 1e-7 | CGS energy |
| Horsepower-hour | hp·h | 2.685e6 | Engine work |
| In-pound force | in·lbf | 0.1129848 | Small mechanical |
| Kilocalorie | kcal | 4184 | Same as Cal |
| kW·h (BOTU) | B.O.T.U. | 3.412e6 | US Board of Trade |
| Litre-atm | l·atm | 101325 | Gas work |
| Quad | quad | 1.055e18 | US energy industry |
| Rydberg | Ry | 2.179872e-18 | Atomic physics |
| Therm (E.C.) | thermEC | 1.055e8 | European gas |
| Thermie | th | 4.1868e6 | Metric ton‐calorie |
| TCE | TCE | 2.94e10 | Tonne coal eq. |
| toe | toe | 4.1868e10 | Tonne oil eq. |
| Ton TNT | tTNT | 4.184e9 | Explosive yield |
| Watt-second | W·s | 1 | Same as Joule |
🧪 Example Conversions
- 10 kW·h to joules: 10 × 3.6×10⁶ = 36,000,000 J
- 500 Cal to kW·h: 500 × 4184 = 2,092,000 J → ÷ 3.6×10⁶ = 0.5811 kW·h
- 2 quads to joules: 2 × 1.055×10¹⁸ = 2.11×10¹⁸ J
- 1000 eV to joules: 1000 × 1.602×10⁻¹⁹ = 1.602×10⁻¹⁶ J
- 200 ft·lbf to kcal: 200 × 1.3558179 = 271.16 J → ÷ 4184 = 0.0648 kcal
💡 Use Cases
- 🔬 Convert food calories to joules for scientific reporting
- 🏠 Translate electricity bills (kW·h) into mechanical energy units
- 🧯 Compare explosive energy (ton of TNT) with chemical energy
- 📉 Analyze energy content of fossil fuels (boe, toe)
- 🔧 Convert between HVAC BTUs and SI units for equipment specs
❓ Frequently Asked Questions
Why is everything converted via joules?
Joule (J) is the SI base unit of energy. Using it as the pivot ensures accuracy and consistency in all conversions.
What is a barrel of oil equivalent (boe)?
1 boe ≈ 5.86 GJ. It's used to compare different energy sources like oil, gas, and electricity on a unified scale.
What’s the difference between Cal and kcal?
They’re the same. In nutrition, 1 Calorie (Cal) = 1 kilocalorie (kcal) = 4184 J.
What is CHUIT?
CHUIT (Celsius Heat Unit, International Table) is equivalent to 1 Calorie or 4184 joules. It’s used in food and fuel energy contexts.
How accurate are the conversions?
All constants are based on ISO or NIST standards. Minor rounding may exist in industrial approximations (e.g., boe, therm).
Can I customize or add more units?
Yes. Modify the toJoules object in energy-converter.js to include additional factors or custom units.
What is a quad?
A “quad” is a unit used in the US energy sector. 1 quad = 10¹⁵ BTUs ≈ 1.055×10¹⁸ J. It's often used for national energy statistics.