Energy Converter
Convert joules, kJ, calories, kcal, kWh, BTU and foot-pounds.
Quick answer
- Formula: Result = Value × (factor of from-unit in joules) ÷ (factor of to-unit in joules)
- Worked example — Converted energy: 3,600,000.000000 (full example below).
Energy Converter
| Converted energy | 3,600,000.000000 |
| Summary | 1 kWh = 3600000 J |
One kilowatt-hour — running a 1 kW heater for an hour — is exactly 3,600,000 joules.
Convert energy through the joule. This converter uses the thermochemical calorie of exactly 4.184 J (so a food 'Calorie', a kilocalorie, is 4184 J), a kilowatt-hour of exactly 3.6 × 10⁶ J, an International Table BTU of 1055.05585262 J, and a foot-pound-force of 1.355817948 J.
Watch out for the two 'calories': food labels use kilocalories. A 2000-Calorie diet is 8.37 million joules — about 2.3 kWh.
The formula
Worked example
One kilowatt-hour — running a 1 kW heater for an hour — is exactly 3,600,000 joules.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
How many joules are in a food Calorie?
4184 J. A food Calorie (capital C) is a kilocalorie — 1000 thermochemical calories of 4.184 J each.
How many BTU are in a kWh?
About 3412 BTU. Air conditioners are rated in BTU per hour; divide by 3412 to get their power in kilowatts.
Which calorie definition is used here?
The thermochemical calorie, defined as exactly 4.184 J. The International Table calorie (4.1868 J) differs by less than 0.07%.
Category: Unit Conversions calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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