kWh to MMBtu Converter

Background.

An electric bill counts kilowatt-hours. A gas bill counts therms, or MMBtu on larger commercial accounts. Anyone with both bills is reading two meters in two different units of energy, and until both are in one unit you cannot say which fuel carries more of the household's load.

The bridge between them is the joule. A kilowatt-hour is exactly 3,600,000 joules, because a watt is one joule per second and an hour has 3,600 seconds. The International Table British thermal unit is fixed at exactly 1,055.05585262 joules, and an MMBtu is a million of them. Divide the first by the second and each kilowatt-hour works out to 3,412.1416 Btu. Turned round, one MMBtu is 293.0711 kWh and one therm, a tenth of an MMBtu, is 29.3071 kWh.

Energy is not the same as useful heat, and that matters as soon as the comparison is about heating. A kilowatt-hour fed to a resistance heater ends up as a kilowatt-hour of warmth in the room, while a therm burned in a furnace loses part of itself up the flue. The conversion tells you how much energy each bill represents; the efficiency of the equipment decides how much of it you felt.

What is kwh to mmbtu converter?

Converting kWh to MMBtu restates an amount of electrical energy in the heat units used to sell natural gas. The kilowatt-hour is one kilowatt sustained for an hour. The British thermal unit began as the heat needed to warm a pound of water by one degree Fahrenheit and is now defined in joules. The double M in MMBtu comes from the Roman numeral M for a thousand, so MM means a thousand thousands: one million Btu. A therm is 100,000 Btu. Several Btu definitions exist; this converter uses the International Table Btu throughout.

How to use this calculator.

1. 01Find the energy used on the electric bill, the figure in kWh for the billing period. Commercial bills often also print a demand figure in kW; that is a peak rate of use, not an amount of energy, so leave it out.
2. 02Enter the kilowatt-hours. Any period works, but compare it with a gas bill covering the same days.
3. 03Read therms to set beside a household gas bill and MMBtu for commercial or wholesale gas quantities.
4. 04If the question is cost rather than energy, price each fuel separately at its own tariff; the Electricity Cost calculator handles the electricity side.

The formula.

MMBtu = kWh × 3,600,000 ÷ 1,055,055,852.62. The numerator is the number of joules in a kilowatt-hour and the denominator the number of joules in a million International Table Btu; both are exact by definition, so the conversion carries no measurement uncertainty at all. Their ratio, 0.0034121416…, has no end to its decimal expansion because the Btu's joule value shares no convenient factors with 3.6 million. The other two results follow by moving the decimal point: therms = MMBtu × 10 and Btu = MMBtu × 1,000,000. Going the other way is simply kWh = MMBtu × 293.0711.

A worked example.

Frequently asked questions.

References& sources.

1. [1]National Institute of Standards and Technology (2008). NIST Special Publication 811 — Guide for the Use of the International System of Units (SI), Appendix B: Conversion Factors. Source for the exact International Table Btu (1055.05585262 J) and kWh-joule equivalence used in this calculator.
2. [2]Bureau International des Poids et Mesures (2019). The International System of Units (SI Brochure), 9th edition. Reference for the joule/watt-hour relationship (1 Wh = 3600 J exactly) underlying the kWh input.