MJ to kWh Converter – Convert Megajoules to Kilowatt Hours

Free online MJ to kWh converter built for American energy math. Decode therms on your gas bill, size propane tanks, and compare furnace vs. heat pump costs with instant, accurate megajoule-to-kilowatt-hour results.

US Energy Converter - Joules, BTUs, kWh & Calories

1 mj = 0.2777777778 kwh

The quick answer for 1 Megajoules — type any value below for the exact result

Enter Megajoules

Megajoules

Result in Kilowatt Hours

kwh

Kilowatt Hours

MJ to kWh Conversion Formula

To convert megajoules to kilowatt hours, divide the MJ value by 3.6 (or multiply by 0.277778). One megajoule is 1,000,000 joules and one kilowatt hour is 3,600,000 joules, so the exact ratio is 1 MJ = 1/3.6 kWh. A handy American anchor: one therm of natural gas = 105.5 MJ = 29.3 kWh.

1 mj = 0.2777777778 kwh

Megajoules and Kilowatt Hours Explained

Megajoules (mj)

The megajoule (MJ) is one million joules, the everyday scale of the SI energy unit. A gas furnace burns tens of megajoules per hour, a gallon of gasoline holds about 120 MJ, and a sprinting cyclist delivers roughly 1 MJ per minute at peak. Fuel suppliers quote natural gas energy content in MJ per cubic meter, making the megajoule the working unit of the gas industry across most of the metric world.

Where it is used: Standard on gas bills in Australia, New Zealand, and much of Asia; common in international fuel energy tables, boiler ratings, and scientific contexts using the related kilojoule for food energy.

Origin: A straight metric multiple of the joule; gas utilities across the metric world adopted MJ billing during metrication, while American utilities kept the therm and Btu inherited from imperial practice.

Kilowatt Hours (kwh)

The kilowatt hour (kWh) is the energy of one kilowatt of power — one thousand watts — sustained for one hour, equal to 3.6 MJ or 3,600,000 joules. It's what US electricity meters count and utilities bill: the average American home uses about 30 kWh per day, an EV battery holds 40-100 kWh, and a desktop computer running all day draws roughly 5-8 kWh.

Where it is used: Universal for electricity billing, EV and home-battery specs, solar generation metering, and EnergyGuide appliance labels.

Origin: Created by early electrical utilities in the 1880s as a billable combination of power and time; despite not being SI, it is legal for trade nearly everywhere, including every US state.

Megajoules to Kilowatt Hours Conversion Table

Megajoules (mj)	Kilowatt Hours (kwh)
1 mj	0.2777777778 kwh
2 mj	0.5555555556 kwh
5 mj	1.3888888889 kwh
10 mj	2.7777777778 kwh
20 mj	5.5555555556 kwh
50 mj	13.8888888889 kwh
100 mj	27.7777777778 kwh
150 mj	41.6666666667 kwh
200 mj	55.5555555556 kwh
250 mj	69.4444444444 kwh
400 mj	111.1111111111 kwh
500 mj	138.8888888889 kwh
1000 mj	277.7777777778 kwh

Kilowatt Hours to Megajoules Conversion Table

Kilowatt Hours (kwh)	Megajoules (mj)
0.1 kwh	0.36 mj
0.25 kwh	0.9 mj
0.5 kwh	1.8 mj
1 kwh	3.6 mj
2 kwh	7.2 mj
5 kwh	18 mj
10 kwh	36 mj
20 kwh	72 mj
30 kwh	108 mj
50 kwh	180 mj
60 kwh	216 mj
100 kwh	360 mj

Megajoules to Kilowatt Hours in Everyday Objects

Common real-world examples that make Megajoules and Kilowatt Hours easy to picture at a glance.

	Megajoules (mj)	Kilowatt Hours (kwh)
A 250-Calorie candy bar	1.046 mj	0.2905555556 kwh
One therm of natural gas	105.506 mj	29.3072222222 kwh
A day of gas heating in a Chicago winter	400 mj	111.1111111111 kwh
A 60 kWh EV battery	216 mj	60 kwh
A standard 20-pound propane tank	414 mj	115 kwh
A month of electricity for an average American home	3240 mj	900 kwh

When You Need Megajoules to Kilowatt Hours Conversions

Comparing Your Gas and Electric Bills

A January gas bill showing 50 therms equals 5,275 MJ — about 1,465 kWh of energy. Priced at your electric rate, that instantly shows what the same heat would cost as electricity, before a heat pump's efficiency gains enter the picture.

Sizing a Water Heater

Gas tankless units are rated in BTU per hour and electric ones in kilowatts. A 199,000 BTU/h model converts to 58.3 kWh of heating per hour — about thirteen times a standard 4.5 kW electric element.

Grilling and Patio Propane Planning

A standard 20-pound propane tank holds about 360 MJ of usable energy — roughly 100 kWh. Converting tank capacity this way tells you how many long cookouts one refill covers before the next exchange at the hardware store.

Furnace vs. Heat Pump Math

Gas furnaces are rated in BTU per hour — 100,000 BTU/h works out to 105.5 MJ/h, or 29.3 kWh of heat. Converting to kWh puts furnace output and a heat pump's electricity draw on one scale for a true running-cost comparison.

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How to Use

1

Enter Megajoules

Type the MJ value from an equipment spec sheet, propane chart, or international gas bill — for example 105.5 MJ, which is exactly one therm, the billing unit on most US gas bills
2

View Kilowatt Hours

The electricity-scale equivalent appears instantly: 105.5 MJ converts to 29.3 kWh, ready to price against your electric rate
3

Copy or Swap

Copy the result or click Swap to convert kilowatt hours back to megajoules for reverse checks
4

Price the Energy

Multiply the kWh result by your electricity rate to compare fuels: at the US average of $0.17 per kWh, one therm of gas (105.5 MJ, or 29.3 kWh) equals about $4.98 of electricity — exactly the math you need when weighing a gas furnace against an electric heat pump

Why Use Be Converter?

Instant Conversion

Get precise MJ to kWh results in real time as you type — perfect for decoding therms on a gas bill or checking a furnace spec sheet

Exact 1/3.6 Ratio

Built on the exact definition 1 kWh = 3.6 MJ, so 360 MJ always lands on exactly 100 kWh with no accumulated rounding

Conversion Table

Quick-reference rows from 1 MJ (0.2778 kWh) through one therm (105.5 MJ = 29.3 kWh) up to 1000 MJ (277.8 kWh)

Bidirectional

Swap between megajoules and kilowatt hours in one click to double-check both directions of a calculation

Free & No Signup

No registration, no limits, completely free — convert as much as you need, whenever you need it

Privacy First

Every calculation runs right in your browser. Nothing you type ever leaves your device

Frequently Asked Questions

How many kilowatt hours are in 1 megajoule?

1 megajoule equals 0.277778 kilowatt hours (exactly 1/3.6). Going the other way, 1 kWh equals 3.6 MJ. So 10 MJ of natural gas — about a tenth of a therm — is roughly 2.78 kWh of electricity-equivalent.

How do I convert 100 MJ to kWh?

Divide by 3.6: 100 ÷ 3.6 = 27.7778 kWh. That's just under one therm — enough energy to run a typical 1,500-watt space heater for more than eighteen hours.

How many kWh is a therm of gas?

One therm — the billing unit on most US gas bills — equals 105.506 MJ, which converts to about 29.3 kWh. A typical household burns 30-60 therms in a winter month, so converting therm → MJ → kWh lets you put gas heating costs side by side with your electric bill.

Why do gas bills overseas show MJ instead of therms?

Most of the metric world — including Australia, New Zealand, and much of Asia — bills natural gas in megajoules, while Canada uses gigajoules (1 GJ = 1,000 MJ) and the US sticks with therms. If you're reviewing a bill from abroad or a spec sheet from an imported appliance, divide MJ by 3.6 to get kWh, then price it against your cents-per-kWh electric rate just like you would at home.

How much gas does a water heater use?

A standard 40- to 50-gallon gas water heater serving a family of four typically burns 70-100 MJ per day, which is 19.4-27.8 kWh of energy. A high-efficiency tankless unit cuts that substantially — one reason MJ-to-kWh math matters when you're comparing gas and electric models at the home center.

What is 1000 MJ in kilowatt hours?

1000 ÷ 3.6 = 277.778 kWh. That's roughly a month of water heating for a family, or about nine days of total electricity for the average American home (around 30 kWh per day).

Is an MJ bigger than a kWh?

No — a kilowatt hour is 3.6 times larger than a megajoule. Converting MJ to kWh should always shrink the number: 500 MJ becomes 138.889 kWh. If your result grew, you multiplied by 3.6 instead of dividing.

How do I convert MJ to kWh in my head?

Use the approximation 1 MJ ≈ 0.28 kWh: 100 MJ ≈ 28 kWh, 400 MJ ≈ 112 kWh. The exact factor is 0.277778, so this shortcut stays within about 1% — good enough for checking bills on the spot.

About Megajoules to Kilowatt Hours Converter

Our free MJ to kWh converter delivers instant, accurate energy conversions for American households and engineers. The US bills natural gas in therms and electricity in kilowatt hours, while megajoules show up on imported heater specs, propane energy charts, fuel data tables, and gas bills from Australia, New Zealand, and much of Asia. Since 1 MJ = 0.277778 kWh exactly, translating between the units is the fastest way to see which fuel is cheaper for heating, hot water, and cooking. You'll also meet MJ in boiler ratings and furnace output tables, and this tool lines those figures up with the kWh counted by your electric meter — from a single megajoule to utility-scale quantities, with an exact definition-based factor.

Expert Tips for MJ to kWh Conversion

The exact ratio is 1 MJ = 1/3.6 kWh = 0.277778 kWh. Memorize two anchors: 360 MJ = 100 kWh and 105.5 MJ = 29.3 kWh (one therm), then interpolate for everything in between.

Comparing your gas and electric bills: each therm is 105.5 MJ ÷ 3.6 = 29.3 kWh. At $1.40 per therm versus the US average of $0.17 per kWh, gas heat works out to roughly 4.8 cents per kWh-equivalent — the raw number a heat pump's efficiency has to beat.

BTU ratings convert through MJ too: a common 100,000 BTU/h furnace equals 105.5 MJ/h, or 29.3 kWh of heat per hour. Chaining BTU → MJ → kWh puts furnace output and electric equipment on one scale.

Water heater shopping: a 199,000 BTU/h tankless gas unit delivers about 210 MJ/h — 58.3 kWh of heat per hour — versus roughly 4.5 kW from a standard electric element, which is why gas units recover faster.

For carbon accounting, converting annual gas use into kWh (therms × 29.3, or MJ ÷ 3.6) puts all your household energy in one column; multiplying by a single grid-emissions factor then gives total CO2 from both fuels.