CCF to Therms Calculator (gas bill CCF, MCF → therms, kWh, cost)

Understanding the CCF to therms calculator — concept and principle

This calculator converts US natural gas meter readings in CCF (hundred cubic feet), MCF or cubic feet into therms, the energy unit gas is billed in. It also gives the energy in kWh, MJ and MMBtu, the volume in cubic metres, the gas energy cost at your price per therm and the cost per CCF. Households checking a gas bill and people comparing gas with electric heating use it.

Gas volume → heat energy — with the default inputs: 66.37 therms.

How it is calculated

CCF = MCF × 10 = cubic feet ÷ 100
Therms = CCF × therm factor (printed on your bill, also called the Btu factor)
MJ = therms × 105.4804; kWh = MJ ÷ 3.6; MMBtu = therms ÷ 10
Cubic metres = CCF × 100 × 0.0283168
Cost = therms × price per therm; cost per CCF = therm factor × price

Fixed monthly charges and taxes are not included.

The principle

A gas meter measures volume, but what you pay for is energy, and the energy in a cubic foot of gas varies with its composition. Utilities therefore apply a therm factor based on the heat content of the gas delivered in the billing period. A therm is 100,000 Btu, so the factor is the heat content in Btu per cubic foot divided by 1,000. The US Energy Information Administration reports an average of about 1,037 Btu per cubic foot for 2025, which gives 1.037 therms per CCF. Converting to kWh uses the US therm of 105.4804 MJ.

Worked example

Defaults: 64 CCF, therm factor 1.037, price 1.45 per therm.

Therms = 64 × 1.037 = 66.37.
Energy = 66.368 × 105.4804 = 7,000.52 MJ = 1,944.59 kWh = 6.637 MMBtu.
Volume = 64 CCF = 6,400 ft³ = 181.23 m³.
Gas energy cost = 66.368 × 1.45 = 96.23; cost per CCF = 1.504.

Gas volume: 64 CCF.

Each point is the calculator re-run with only “Gas used (from your meter or bill)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Gas used (from your meter or bill)	Therms
16	16.59
32	33.18
48	49.78
64	66.37
80	82.96
96	99.55
128	132.74

How to read the result

Compare the kWh figure with electricity to see what heating with gas means in electrical terms; remember that furnaces and heat pumps have different efficiencies. If your bill's therm factor changes from month to month, that reflects the gas's heat content, not a pricing error. Your total bill is higher than the energy cost because of fixed customer charges and taxes.

Common mistakes

Using the default 1.037 instead of the factor printed on your bill.
Confusing CCF with MCF (a factor of 10).
Comparing gas and electricity costs without accounting for appliance efficiency.
Leaving out fixed charges when estimating the full bill.

Keep in mind: Billing rules differ by utility. Use your bill's own therm factor and rates for accurate figures.

Frequently asked questions

How many therms are in a CCF?

About 1.037 at the 2025 US average heat content; your bill shows the exact factor.

What is the difference between CCF and MCF?

CCF is 100 cubic feet; MCF is 1,000 cubic feet.

How many kWh is a therm?

About 29.3 kWh, since 1 therm = 105.4804 MJ and 1 kWh = 3.6 MJ.

Sources: U.S. Energy Information Administration, FAQ "What are Ccf, Mcf, Btu, and therms? How do I convert natural gas consumption data?" · NIST Special Publication 811 (2008 ed.), Appendix B.9

Checked 9 Nov 2026. U.S. Energy Information Administration, FAQ “What are Ccf, Mcf, Btu, and therms? How do I convert natural gas consumption data?” (2025 heat content about 1,037 Btu per cubic foot; 1 Ccf = 1.037 therms); NIST Special Publication 811 (2008 ed.), Guide for the Use of the International System of Units (SI), Appendix B.9 “Factors for units listed by kind of quantity or field of science” — therm (U.S.) = 1.054 804 E+08 J, cubic foot = 2.831 685 E-02 m³.

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