CalcLibrary

Energy Converter

Convert a known energy amount between joules, watt-hours, food Calories, and BTU. Built for bills, food labels, appliance specs, and formulas that expect a different energy unit.

Examples

Translate an electricity-bill unit into a science-style energy unit.

Converted energy
3.6 MJ
Joule conversion path
1 kWh × (3600000 J/kWh) ÷ (1000000 J/MJ) = 3.6 MJ

The result is larger because the target unit is smaller. One source unit contains about 3.60 target units.

Unit converter only — it does not estimate cost, appliance efficiency, nutrition guidance, or derived physics quantities.

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Examples

How It Works

Formula

r=v×ffromftor = v \times \dfrac{f_{\text{from}}}{f_{\text{to}}}

Variables

vv

Input energy value

rr

Converted energy value

ffromf_{\text{from}}

Joules per source unit(J)

ftof_{\text{to}}

Joules per target unit(J)

Each supported unit maps to a fixed number of joules. Your entered value is first converted into joules, then converted again into the target unit. That keeps science units, household electricity units, nutrition units, and BTU on one clear reference basis.

Reference factors used by the calculator (joules per unit):

  • 1 J = 1 J
  • 1 kJ = 1000 J
  • 1 MJ = 1000000 J
  • 1 Wh = 3600 J
  • 1 kWh = 3600000 J
  • 1 cal = 4.184 J (thermochemical calorie)
  • 1 kcal = 4184 J (food Calorie / thermochemical kilocalorie)
  • 1 BTU = 1055.05585262 J (International Table Btu)

The value is first multiplied by the source factor to get joules, then divided by the target factor to land in the chosen unit.

Frequently Asked Questions

01What is the difference between cal and kcal / Calories?
A small calorie (cal) is about 4.184 joules. A kilocalorie (kcal) equals 1000 cal and is the same unit commonly labeled as a food Calorie with a capital C.
02Which BTU definition does this calculator use?
It uses the International Table BTU (BtuIT), defined here as 1055.05585262 joules. Other BTU variants exist, so the calculator names this choice explicitly instead of hiding it.
03How does the calculator convert between units?
Each supported unit is mapped to a fixed number of joules. The calculator multiplies your source value into joules first, then divides by the target unit factor.
04Why does every conversion go through joules first?
Joules are the canonical SI energy unit, so routing through joules keeps every pair on one auditable base instead of relying on many pair-specific formulas.
05How is this different from electricity cost, cooking, or physics calculators?
This tool only converts one known energy amount between units. Use electricity-cost-calculator for billing estimates, cooking-converter for kitchen volume and weight work, and kinetic-energy or potential-energy for derived physics quantities.

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