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Energy Converter

J · kJ · MJ · Wh · kWh · MWh · BTU · cal · eV

Free energy converter: joules, kWh, BTU, calories, and electronvolts. Convert electron volt to joules, kWh to J, BTU to kJ, or kcal to kJ — instant conversion of units of energy with formulas below.

Use for electricity bills (kWh / "units"), food labels (kcal), HVAC specs (BTU), and physics (convert ev to j). No upload, no sign-up.

Value (kWh)
Result (J)

3,600,000

All unit equivalents

Mathematical / technical context

All energies normalize to joules (J), the SI base unit.

1 kWh = 3.6 × 10⁶ J · 1 BTU ≈ 1,055 J · 1 kcal = 4,184 J · 1 eV = 1.602 × 10⁻¹⁹ J

Step-by-step energy conversion examples

kWh → J: 1 kWh × 3,600,000 = 3,600,000 J (3.6 MJ)

eV → J: 1 eV × 1.602 × 10⁻¹⁹ = 1.602 × 10⁻¹⁹ J

BTU → kJ: 1 BTU × 1.055 = 1.055 kJ

MWh → kWh: 1 MWh × 1,000 = 1,000 kWh

Energy conversion reference table

FromToResult
1 kWhJ3,600,000 J
1 kWhMJ3.6 MJ
1 kWhBTU3,412 BTU
1 BTUkJ1.055 kJ
1 kcalkJ4.184 kJ
1 eVJ1.602 × 10⁻¹⁹ J
1 MWhkWh1,000 kWh
1 MWhJ3.6 × 10⁹ J
1 WhJ3,600 J
1 GJBTU≈ 947,817 BTU
2 kWhJ7.2 × 10⁶ J
1 JeV6.242 × 10¹⁸ eV

Complete guide to joules, kWh, BTU & energy unit conversion

Energy converter — joules, kWh, BTU, calories, and eV online

An energy converter translates how much work or heat is stored from one unit to another. This free tool handles joules (J), kilojoules (kJ), megajoules (MJ), watt-hours (Wh), kilowatt-hours (kWh), megawatt-hours (MWh), BTU, calories (cal/kcal), and electronvolts (eV) — for electricity bills, nutrition labels, HVAC specs, and physics homework.

Whether you need conversion of units of energy, units to measure energy, or practical energy conversion examples, pick From and To in the dropdowns. All conversion energy math runs locally — nothing is uploaded.

Energy vs power — why kW is not the same as kWh

Many searches mix energy and power. This tool converts energy (total amount). Power (watts, kilowatts) is energy per unit time.

  • 1 kilowatt to watt / convert watt into kilowatt — power scaling: 1 kW = 1,000 W (not handled here; use a power converter).
  • 1 watt power sustained for one hour = 1 Wh of energy.
  • Conversion of power to energy / energy to power conversion: multiply power (W) by time (hours) to get Wh, or divide energy by time to get watts.

Searches like watt to kilowatt hour calculator, watt kwh converter, or convert watts to kilowatt hours mean: energy (kWh) = power (kW) × time (h). Example: a 2 kW heater for 3 hours = 6 kWh. Enter 6 kWh here to convert to joules or BTU.

Horse power to kilowatt conversion calculator and electric power converter are power tools — 1 hp ≈ 745.7 W. This page converts the resulting energy once you know kWh or joules.

kWh, watt-hours, and electricity units

Electrical energy on utility bills is billed in kilowatt-hours (kWh). In India and some regions, one kWh is colloquially called one "unit" of electricity.

Kilowatt to unit conversion, 1 kilowatt to unit conversion, convert kilowatt to unit, kilowatt hour to unit converter, kilowatt into unit, and 1kw convert to unit: 1 kWh = 1 "unit" on many domestic meters. Convert unit to kilowatt / convert watts to units: divide energy (Wh) by 1,000 for kWh units.

1 kWh = 1,000 Wh = 3,600,000 J = 3.6 MJ

Convert megawatt hours to kilowatt hours: 1 MWh = 1,000 kWh. Megawatt to unit conversion: 1 MWh = 1,000 electricity units (where 1 unit = 1 kWh). Kw kwh converter and kilowatt hour to kilowatt confuse rate with total — kWh already includes the hour factor.

Kw hour calculator / ah to kwh calculator / ah to watt hour conversion / convert mah to watt hour: battery capacity (Ah × voltage = Wh) needs voltage — use Wh or kWh directly in this converter once you have watt-hours.

Joules, BTU, and calories — common energy conversion

The SI unit is the joule (J). Key factors for energy conversion:

1 kWh = 3.6 × 10⁶ J · 1 BTU ≈ 1,055 J · 1 kcal = 4,184 J · 1 cal ≈ 4.184 J

British thermal unit conversion / btu unit conversion: 1 BTU ≈ 1.055 kJ. Btu to kilowatt often means BTU/h (a power rate for HVAC) — for energy, 1 BTU ≈ 0.000293 kWh. 100000 btu to kw as power ≈ 29.3 kW heating capacity; as energy, 100,000 BTU ≈ 29.3 kWh.

Btu to gj natural gas / btu to mmbtu calculator: 1 GJ = 10⁹ J ≈ 947,817 BTU · 1 MMBtu ≈ 1.055 GJ. Convert BTU → joules here, then scale to GJ. 3.5 kw to btu converter (HVAC) is typically BTU/h ↔ kW — power, not energy.

Food labels use kilocalories (kcal) — often written "Calories." 2,000 kcal/day ≈ 8,368 kJ ≈ 2.33 kWh of food energy (not all absorbed as usable work).

Electron volt to joules — eV and joule conversion

In atomic and particle physics, energy is quoted in electronvolts (eV). Searches include electron volt to joules, convert ev to j, joule to ev conversion, convert joule to ev, and joule ev conversion.

1 eV = 1.602176634 × 10⁻¹⁹ J  ·  1 J ≈ 6.242 × 10¹⁸ eV

That constant matches 1.60217663 × 10⁻¹⁹ joules per electronvolt (2019 SI definition). Example: 1 MeV = 10⁶ eV ≈ 1.602 × 10⁻¹³ J. Volts to electron volts conversion is different — eV is an energy unit (charge × voltage), not a voltage conversion.

Convert 1 joule into erg: 1 J = 10⁷ erg (CGS unit not in the dropdown — multiply joules by 10,000,000 mentally, or convert J → kJ here for SI work).

Energy conversion examples — practical anchors

Useful energy conversion examples for quick checks:

  • 1 kWh = 3,600,000 J = 3.6 MJ = 3,412 BTU
  • 1 BTU ≈ 1.055 kJ ≈ 0.293 Wh
  • 1 kcal ≈ 4.184 kJ ≈ 3.97 BTU
  • 9 kWh ≈ 32.4 MJ (typical daily home use in many countries)
  • 1 eV ≈ 1.602 × 10⁻¹⁹ J (single atomic-scale quantum)

2kw convert to watts is power (2,000 W). If that device runs 1 hour, it consumes 2 kWh — convert that here to joules or BTU.

What this energy converter is not

This tool converts energy units — not the physical processes behind them. Searches like heat to electricity converter, turning heat into electricity, conversion of mechanical energy to electrical energy, mechanical energy to electrical energy, chemical energy into electrical energy, electrical energy into mechanical energy, electricity to heat conversion, coal to electricity energy conversion, or principles of energy conversion describe thermodynamics, generators, and power plants — not unit arithmetic.

Likewise: natural gas conversion calculator, gas to hydrogen conversion, coal to co2 conversion, and btu to scf natural gas involve fuel chemistry and volume–energy relationships beyond simple J ↔ BTU scaling. Once you have an energy value in BTU or kWh, this converter handles the unit switch.

Joule to kg uses E = mc² (mass–energy equivalence) — not a linear unit factor. Unit converter power belongs in a watts/horsepower tool. For pure energy power conversion between J, kWh, BTU, cal, and eV, this page is the right place.

Detailed guide

Energy vs power

kWh measures total energy consumed. kW measures how fast energy is used. A 2 kW device running 3 hours uses 6 kWh — convert that 6 kWh here to joules or BTU.

Electricity 'units'

On many domestic meters, especially in India, 1 kWh equals 1 billed "unit." 100 units = 100 kWh.

eV in physics

Electronvolts describe atomic-scale energies — chemical bonds, photon energies, particle physics. 1 eV = 1.602 × 10⁻¹⁹ J exactly (2019 SI).

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Common questions

Energy units — joules, kWh, BTU & eV FAQ

kWh to joules?

Multiply kWh by 3,600,000. 1 kWh = 3.6 × 10⁶ J.

Electron volt to joules?

Multiply eV by 1.602176634 × 10⁻¹⁹. 1 eV ≈ 1.602 × 10⁻¹⁹ J.

Joule to eV?

Divide joules by 1.602 × 10⁻¹⁹, or multiply by 6.242 × 10¹⁸.

BTU to kJ?

Multiply BTU by 1.055.

BTU to kWh?

Multiply BTU by 0.000293.

1 kWh in BTU?

≈ 3,412 BTU.

Calorie to joule?

1 cal ≈ 4.184 J. 1 kcal = 4,184 J.

MWh to kWh?

Multiply MWh by 1,000.

What is 1 kWh in 'units'?

On many electricity meters, 1 unit = 1 kWh.

Is kW the same as kWh?

No. kW is power (rate). kWh is energy (power × time).

Is data uploaded?

No — all energy conversion runs locally in your browser.