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Energy Converter

Energy & Power

Convert energy units instantly — joules, kWh, BTU, calories, and more. Essential for electricity bills, nutrition labels, and engineering calculations in India.

From
To
All conversionsfor 1 Kilowatt-hours (kWh)
Joules (J)3600000
Kilojoules (kJ)3600
Megajoules (MJ)3.6
Calories (cal)860420.65
Kilocalories / Calories (kcal)860.42065
British Thermal Units (BTU)3412.1416
Watt-hours (Wh)1000
Kilowatt-hours (kWh)1
Megawatt-hours (MWh)0.001
Electronvolts (eV)2.2469e+25
Foot-pounds (ft·lbf)2655223.7

What is a Energy?

An Energy Converter translates quantities of energy between the unit systems used across science, engineering, nutrition, and everyday life — joules, kilojoules, megajoules, kilowatt-hours, British Thermal Units, calories, kilocalories, watt-hours, megawatt-hours, electronvolts, and foot-pounds.

Energy is a single physical quantity, but it is expressed in radically different units depending on context. An Indian electricity bill counts units in kWh. Food packaging in India lists energy in kcal (often labelled simply as 'Calories'). Air conditioner cooling capacity is quoted in BTU per hour. Mechanical engineering specs use joules or foot-pounds. Nuclear and semiconductor physics uses electronvolts. This fragmentation makes direct comparison impossible without conversion.

In India, energy literacy is increasingly important. Electricity tariffs from DISCOMs like BESCOM, MSEDCL, TNEB, and CESC are structured in kWh slabs — understanding how appliance wattage translates into kWh consumed per month directly affects your electricity bill. The Bureau of Energy Efficiency (BEE) star ratings on refrigerators, ACs, and motors give Annual Energy Consumption (AEC) in kWh, which this converter can translate into joules or BTU for engineering cross-checks.

On the nutrition side, India's Food Safety and Standards Authority (FSSAI) mandates energy labelling in kcal per 100 g on packaged foods. Converting these to kJ is useful for those reading European nutrition research, and converting to joules helps when relating food intake to mechanical work output in sports science.

All 11 units in this converter are anchored to the joule as the SI base unit, making every conversion exact and mathematically consistent. For power-related calculations (energy per unit time), see the Power Converter.

How to use this Energy calculator

  1. Select your source unit from the FROM dropdown — e.g. Kilowatt-hours (kWh).
  2. Enter your numeric value in the input field — e.g. 10 for 10 kWh.
  3. Select the target unit from the TO dropdown — e.g. British Thermal Units (BTU).
  4. The converted result appears instantly — no button press needed.
  5. Use the ⇅ swap button to reverse FROM and TO in one click.
  6. Scroll to the reference table to see your value in all 11 units simultaneously.
  7. Copy the page URL to share or bookmark this exact conversion.

Formula & Methodology

All units convert to and from joules (J) using exact multipliers:

| Unit | Symbol | Joules (toBase) |
|---|---|---|
| Joule | J | 1 (base) |
| Kilojoule | kJ | 1,000 |
| Megajoule | MJ | 1,000,000 |
| Calorie (thermochemical) | cal | 4.184 |
| Kilocalorie | kcal | 4,184 |
| British Thermal Unit | BTU | 1,055.05585 |
| Watt-hour | Wh | 3,600 |
| Kilowatt-hour | kWh | 3,600,000 |
| Megawatt-hour | MWh | 3,600,000,000 |
| Electronvolt | eV | 1.602176634 × 10⁻¹⁹ |
| Foot-pound | ft·lbf | 1.3558179483 |

Conversion formula: Result = Input × (F_from ÷ F_to)

Worked example — AC energy cost in India:

A 1.5-tonne split AC draws 1.5 kW and is rated at 18,000 BTU/hr. How much does running it for 8 hours cost at ₹7/unit?

Energy consumed = 1.5 kW × 8 h = 12 kWh Cost = 12 × ₹7 = ₹84  Cross-check in BTU: 12 kWh × 3,412.14 BTU/kWh = 40,945 BTU Cooling delivered = 18,000 BTU/hr × 8 hr = 144,000 BTU

Common reference values:

| Quantity | Energy |
|---|---|
| 1 Indian electricity 'unit' | 1 kWh = 3.6 MJ |
| 500 kcal meal | 2,092 kJ = 0.581 kWh |
| 1 litre of petrol | ≈ 34 MJ ≈ 9.44 kWh |
| 1 kg LPG | ≈ 49 MJ ≈ 13.6 kWh |
Frequently Asked Questions
What is an energy converter?
An energy converter is a tool that translates a quantity of energy from one unit to another — such as from kilowatt-hours (kWh) to British Thermal Units (BTU) or from kilocalories (kcal) to joules (J). Energy is measured in different units depending on context: electricity bills use kWh, food labels use kcal, engineering uses joules or BTU, and physics uses electronvolts. This converter handles all major energy units in a single step.
What is the difference between a calorie and a kilocalorie?
A calorie (cal) is the amount of energy needed to raise 1 gram of water by 1°C, while a kilocalorie (kcal) is 1,000 calories. The 'Calories' printed on food packaging in India and most countries are actually kilocalories — so a food item labelled '200 Calories' contains 200 kcal or 200,000 cal. This converter uses the thermochemical calorie (1 cal = 4.184 J exactly) as the standard definition.
How do I convert kWh to joules?
Multiply the number of kilowatt-hours by 3,600,000 to get joules, since 1 kWh = 1,000 W × 3,600 s = 3,600,000 J. For example, 5 kWh = 5 × 3,600,000 = 18,000,000 J = 18 MJ. This conversion is useful when comparing electrical energy consumption with mechanical or thermal energy specifications.
What is a BTU and when is it used in India?
A BTU (British Thermal Unit) is the energy needed to raise 1 pound of water by 1°F, equal to approximately 1,055 joules. In India, BTU ratings are used primarily for air conditioners — a 1.5-tonne AC is rated at roughly 18,000 BTU/hr of cooling capacity. When shopping for ACs, comparing BTU figures across brands is common, and this converter lets you cross-check against SI power units.
How many joules are in a kWh?
One kilowatt-hour (kWh) equals exactly 3,600,000 joules (3.6 MJ). This is because 1 kWh = 1 kilowatt × 1 hour = 1,000 watts × 3,600 seconds = 3,600,000 watt-seconds = 3,600,000 joules. Your monthly electricity bill from BESCOM, MSEDCL, or any Indian DISCOM is denominated in kWh (referred to as 'units' in common parlance).
What is an electronvolt and when is it used?
An electronvolt (eV) is the kinetic energy gained by a single electron accelerated through 1 volt of electric potential, equal to exactly 1.602176634 × 10⁻¹⁹ joules (exact by 2019 SI redefinition). Electronvolts are used in atomic physics, nuclear physics, and semiconductor engineering to describe particle energies and bandgaps. They are not practical for everyday energy quantities but appear in material science and quantum mechanics contexts.
How does India measure energy consumption on electricity bills?
Indian electricity bills measure consumption in kilowatt-hours (kWh), commonly called 'units'. One unit = 1 kWh. If you run a 100-watt bulb for 10 hours, you consume 1 unit. Indian residential tariffs typically range from ₹3 to ₹9 per unit depending on the DISCOM and consumption slab, with higher slabs charged at progressively higher rates under the Time of Day (ToD) or block tariff structures.
How do I use the Energy Converter?
Select the source unit from the FROM dropdown — for example, 'Kilowatt-hours (kWh)'. Enter your value in the input field, such as 10 for 10 kWh. Choose your target unit in the TO dropdown, such as 'British Thermal Units (BTU)'. The result appears instantly. Use the ⇅ swap button to reverse direction, and view the reference table below to see your value expressed in all 11 units at once.
What is the formula for converting BTU to kWh?
Divide the BTU value by 3,412.14 to get kWh. This comes from 1 kWh = 3,600,000 J and 1 BTU = 1,055.06 J, so 1 kWh = 3,600,000 / 1,055.06 = 3,412.14 BTU. Reversing: 1 BTU = 1/3,412.14 kWh ≈ 0.000293 kWh. For air conditioner energy use in India, converting the BTU/hr cooling rating to kW helps estimate running costs at your local electricity tariff.
What is a foot-pound of energy?
A foot-pound (ft·lbf) is an imperial unit of energy equal to the work done by a force of 1 pound-force acting through a distance of 1 foot, approximately 1.3558 joules. It is rarely used in everyday Indian contexts but appears in mechanical engineering specs, gun ballistics (muzzle energy), and American automotive manuals. Torque is also measured in ft·lbf, which is a separate quantity but the same unit dimensionally.
How much energy does a typical Indian household use per month?
The average Indian household consumes between 90 and 300 kWh per month, depending on location, climate, and appliance usage. Urban households with air conditioning typically use 200–400 kWh in summer. The Bureau of Energy Efficiency (BEE) star-rating system on appliances helps consumers estimate monthly consumption: a 5-star 1.5-tonne split AC typically uses about 1 kWh per hour of operation at standard conditions.
What is the relationship between joules, kilojoules, and megajoules?
Joules, kilojoules, and megajoules follow standard SI prefixes: 1 kJ = 1,000 J and 1 MJ = 1,000,000 J = 1,000 kJ. In nutrition, food energy is often expressed in kilojoules (kJ) on European labels — a medium-sized apple contains roughly 250 kJ (60 kcal). In fuels, calorific values are expressed in MJ per kg: natural gas is about 55 MJ/kg, petrol is approximately 44 MJ/kg.

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