energy unit converter

Convert Energy units, compare 15 unit definitions and explore formulas, examples and common questions.

Energy converter

Worked example1 BTU ≈ 1.05505585 kJ
Converted value

1British thermal units≈1.05505585Kilojoules

Enter a finite value between 0 and 1 trillion, with up to 8 decimal places.

Auto mode preserves significant digits for small values; manual mode rounds to the selected decimal places. ≈ means approximate; < means below the display limit. Extreme values use × 10ⁿ. Calculations are rounded only for display.

Complete unit directory15 units

Choose a source unit to see every available target unit. Each directory has a stable address.

How to use this calculator

  1. Enter the value you want to convert.
  2. Choose the source and target units, then adjust the display precision if needed.
  3. Read the result. Select Convert to open a page for this value, or use the table below.

Definitions and assumptions

Energy factors are expressed relative to joules. This tool uses the thermochemical calorie (4.184 J) and the International Table British thermal unit. Energy and torque can share dimensions but describe different physical quantities.

Frequently asked questions

Which Energy units are supported?

The directory lists 15 units, including symbols and availability. Choose any source unit to browse its target units.

how to convert BTU to kJ?

The calculator converts the input to the category's reference unit, then divides by the target unit's factor. 1 × 1.05505585262 ≈ 1.05505585 Kilojoules. Use the source and target factors shown in the formula. The worked example uses the value on this page, and the table provides other common values.

Are all calories identical?

No. Several historical calorie definitions exist. This tool uses the thermochemical calorie of exactly 4.184 joules; a kilocalorie is 1000 of these calories.

Why is the displayed result rounded?

Auto mode preserves significant digits for small values; manual mode rounds to the selected decimal places. ≈ means approximate; < means below the display limit. Extreme values use × 10ⁿ. Calculations are rounded only for display.

What input range can I use?

This calculator accepts non-negative values up to 1 trillion, with up to 8 decimal places. It does not calculate signed vectors or calendar date intervals.

Why is a unit unavailable?

A conversion is unavailable when a verified unit definition or a current exchange-rate value has not been configured. The tool does not invent a coefficient.

Sources and methodology

Methods and sources · Content revised

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