Barrels of Oil Equivalent to Therm (US)

One BOE equals approximately 6.118 gigajoules, 1,700 kWh, or 5.8 million BTU. That is roughly the energy a US household uses in electricity over six weeks. The figure is a defined convention — actual crude oil barrels vary by 5–10% depending on whether it is light sweet crude or heavy sour crude.

Because modern energy companies produce oil, natural gas, and natural gas liquids. Reporting everything in BOE allows investors to compare total energy reserves across companies on one scale. Roughly 6,000 cubic feet of natural gas equals 1 BOE. Without this conversion, comparing an oil-heavy company to a gas-heavy one would be apples-to-oranges.

Global oil consumption in 2024 was approximately 102 million barrels per day — or about 102 million BOE/day just from oil. Including natural gas and coal, total world primary energy consumption is roughly 580 million BOE/day equivalent. The US alone accounts for about 20 million barrels per day.

A physical barrel of crude oil is 42 US gallons (~159 liters) of liquid petroleum. A BOE is a standardized energy unit pegged to the average energy content of that barrel (6.118 GJ). Light crudes like Brent may actually yield slightly more energy per barrel, while heavy crudes yield less. The BOE smooths out these differences for accounting purposes.

A typical EV driven 20,000 km/year consumes about 3,500 kWh, which is roughly 2 BOE of energy. A petrol car covering the same distance burns about 1,500 liters of fuel — approximately 9.5 BOE. The EV uses roughly one-fifth the primary energy, largely because electric motors are 85–95% efficient while combustion engines waste 60–75% as heat.

Residential US natural gas prices typically range from $0.80 to $2.50 per therm depending on region, season, and utility. The wholesale Henry Hub benchmark translates to about $0.25 per therm at $2.50/MMBtu. Delivery charges, taxes, and utility markups roughly triple or quadruple the commodity cost by the time it reaches a home meter.

The average US home using gas for heating consumes about 500–900 therms per year, depending on climate, insulation, and home size. Homes in mild climates like Southern California may use under 300 therms; homes in Minnesota or Wisconsin can exceed 1,200 therms. Gas water heaters alone account for roughly 150–250 therms per year.

One US therm equals exactly 100,000 BTU, while one MMBtu (million BTU) equals 1,000,000 BTU — so 1 MMBtu equals 10 therms. Wholesale gas markets and pipeline contracts use MMBtu; residential utility bills use therms. The two are straightforward to convert, but confusing them by a factor of ten is a common mistake in energy cost comparisons.

Retail billing in therms gives homeowners manageable numbers — a winter month might be 80–120 therms at $1–2 each. Wholesale pipeline contracts deal in millions of BTU (MMBtu) because the volumes are enormous and the industry standardized on BTU-based pricing in the early 20th century. One MMBtu equals 10 therms, so converting is simple. The Henry Hub benchmark price of $2.50/MMBtu translates to about $0.25/therm before delivery charges, taxes, and utility markup roughly quadruple it at the meter.

A typical US residential furnace rated at 80,000–100,000 BTU/h uses about 0.8–1.0 therms per hour at full output. High-efficiency condensing furnaces (95%+ AFUE) extract more heat per therm, so they cycle less often. On a cold winter day, a furnace might run 8–12 hours total, consuming 6–10 therms. That translates to roughly $5–$25 per day depending on local gas prices.