What Is a CCF? How Gas and Water Bills Measure Your Use

A gas meter or a water meter counts the volume that passes through it, and many meters count in cubic feet. Billing every cubic foot would produce huge numbers, so utilities bill in units of 100. One CCF is 100 cubic feet. Ten CCF is 1,000 cubic feet, also written as 1 Mcf.

The unit measures volume, not energy. For natural gas, the energy in a cubic foot changes a little with the gas mix, so utilities convert volume to therms using a factor shown on the bill.

Source: Gas heat content uses EIA's U.S. average of 1,036 Btu per cubic foot for natural gas delivered to consumers, and 3,412 Btu per kWh, from the EIA energy conversion page. Your bill shows its own factor. Water: one cubic foot is 7.48 gallons.

The gas figures follow from the heat content. One CCF is 100 cubic feet, times 1,036 Btu, which is 103,600 Btu. A therm is 100,000 Btu, so a CCF is 1.036 therms. Divide 103,600 by 3,412 Btu per kWh to get 30.4 kWh.

Say your gas meter shows 45 CCF for the month. At 1.036 therms per CCF, that is 46.6 therms. At an assumed all-in price of $1.40 per therm, a made-up figure for the example, the gas costs $65.27, before any fixed monthly charge.

To compare with electric heat, convert to kWh. 45 CCF is about 1,366 kWh of heat. At the 2025 US average of 17.23 cents per kWh, that much heat from a resistance heater would cost $235.49. A furnace wastes some of the gas as exhaust, and a heat pump delivers more heat than the electricity it uses, so the real comparison needs those efficiencies. The heat pump versus furnace calculator includes them.

Water utilities use the same unit. A household that uses 7 CCF in a month used about 5,236 gallons. Some water bills show 1,000 gallons instead, and some show a separate sewer charge based on the same CCF. Check the unit on your own bill before you compare months or homes.

Billing is based on the difference between two readings. Take the current reading, subtract the previous one, and the result is the volume used. If your meter shows cubic feet, divide by 100 to get CCF. Many utility meters already display hundreds of cubic feet, so check the label on the dial face.

Say the previous reading was 4,210 and the current reading is 4,255, with the meter counting in CCF. That is 45 CCF for the period. If the meter counts cubic feet, a change of 4,500 is also 45 CCF.

A gas bill usually has a fixed monthly customer charge, a delivery charge and a charge for the gas itself. Some utilities price delivery and gas per CCF, and some per therm after converting with the heat factor. The bill lists the factor, often as therm factor or BTU factor.

Two utilities can both quote a price per CCF and still differ in what you get, because the heat in a CCF changes with the gas mix. When you compare gas prices between places, compare them per therm.

• Treating CCF and Mcf as the same. An Mcf is ten CCF.
• Comparing a water CCF with a gas CCF. Both are 100 cubic feet, but one is a volume of water and the other a volume of gas, so they do not measure the same thing.
• Ignoring the heat factor when you compare a gas bill with an electric bill.
• Assuming a CCF always converts the same way. It varies a little by utility and by month.
• Reading the wrong dial. On older meters, read each dial from left to right and record the number the pointer has just passed, not the one it is approaching.

• EIA, Energy conversion calculators