MMBtu
Million British thermal units, the standard energy unit for natural gas contracts; about the heat content of 1,000 cubic feet of gas.
One MMBtu equals one million British thermal units, a unit of heat energy. US natural gas and many LNG contracts are priced per MMBtu. The heat content of gas varies slightly with its composition, so converting from volume uses an approximate factor, and contracts specify the conversion they use.
Traders care because pricing in MMBtu lets natural gas, LNG and other fuels be compared on energy content. The difference between regional prices per MMBtu is an input to shipping and export decisions. Always check which heat content basis a contract or data series uses.
Worked example (illustrative numbers, not real data): gas at 3.50 dollars per MMBtu makes a 100,000 MMBtu delivery worth 350,000 dollars.