MMBtu (MMBtu)

A British thermal unit (Btu) is the amount of energy needed to raise one pound of water by one degree Fahrenheit. Because a single Btu is tiny — roughly the energy released by burning one match — natural gas is traded in millions of them, hence MMBtu. The double-M follows Roman numeral convention where M means 1,000 and MM means 1,000,000. Using an energy unit rather than a volume unit (like cubic feet) makes sense because buyers of gas ultimately care how much heat or electricity it can produce.

When you see a natural gas price on a data page, the number represents dollars per MMBtu at a specific hub, most commonly Henry Hub. Suppose gas trades at $3.00 per MMBtu (a hypothetical example): a standard NYMEX futures contract covering 10,000 MMBtu would have a notional value of $30,000. A $0.50 rise in the per-MMBtu price would add $5,000 to that contract's value.

One source of confusion is that natural gas is sometimes also measured in cubic feet (cf), thousand cubic feet (Mcf), or billion cubic feet (Bcf) in production and storage reports. These are volume measures, not energy measures. To convert, one Mcf of typical pipeline-quality natural gas contains roughly 1.02 MMBtu — close enough that traders often treat them as approximately equal, but the distinction matters for precise contract settlement. The commodity units guide covers how these conversions affect price comparisons.