Natural Gas Cost Calculator

Natural gas is measured by volume but often priced by energy, and the two are easy to mix up. Your meter counts cubic feet, usually in hundreds (CCF) or thousands (Mcf), while many utilities bill per therm, a unit of energy equal to 100,000 Btu. This calculator converts between them, prices the result, estimates the gas use of any appliance from its Btu rating and shows what the same heat would cost from electricity. Every figure on this page was computed with the calculator's own formulas.

For the electric side of your utility costs, the Electricity Cost Calculator prices any appliance by its wattage, and the BTU Calculator estimates how much heating capacity a room needs. If an electric car is part of the household budget, the EV Charging Calculator and the EV vs Gas Calculator show what it adds to the power bill.

Therms, CCF and Mcf: reading a gas bill

• CCF: 100 cubic feet of gas, the most common meter unit. Mcf is 1,000 cubic feet, or 10 CCF.
• Therm: 100,000 Btu of energy, the unit many utilities use for pricing.
• Therm factor: also called the Btu factor, the energy content of the gas your utility delivered, in therms per CCF. Because the energy in a cubic foot of gas varies, the utility multiplies your metered volume by this factor to get therms.

EIA reports that in 2025 the natural gas delivered to U.S. end users averaged about 1,037 Btu per cubic foot. That makes 1 CCF = 103,700 Btu = 1.037 therms, and 1 Mcf = 10.37 therms, the conversions this calculator uses by default. A bill that shows 95 CCF and a therm factor of 1.037 therefore charges you for 98.515 therms. If your bill prints a different factor, enter it: the conversion is only as good as the heat content behind it.

The natural gas cost formulas

The appliance formula uses the input rating on the rating plate, which is the gas the appliance burns per hour while the burner fires, not the heat it delivers. A furnace's annual fuel utilization efficiency (AFUE) tells you how much of that gas ends up as heat in the house, which is the number that matters when you compare gas with electric heat.

Worked example 1: a January bill in CCF

A bill shows 95 CCF used and a therm factor of 1.037. Price it at the 2025 U.S. average residential price of $15.34 per Mcf, which is $1.534 per CCF or $1.48 per therm:

The EIA average is an all-in figure: it already spreads fixed customer charges across every unit sold, so nothing is added on top. Now suppose the bill itemizes instead, with example rates of $0.62 per therm for gas supply, $0.71 per therm for delivery, a $15 monthly customer charge and 6% in taxes and fees. The energy charge is 98.515 × $1.33 = $131.02; adding the $15.00 charge gives $146.02, and 6% adds $8.76 for a total of $154.79. Divided by the 98.515 therms used, that is an all-in $1.571 per therm, 18% above the $1.33 of per-therm rates, which is why the all-in price is the one to compare across months and utilities.

Worked example 2: how much gas a furnace uses

A furnace with an input rating of 80,000 Btu per hour fires for a total of 6 hours a day during a 31-day January:

In meter units, 148.8 therms is 143.5 CCF. The same 13.39 million Btu of heat would take 3,925 kWh from electric resistance heat, which costs $706.49 at 18 cents per kWh, or 1,353 kWh from a heat pump with a seasonal COP of 2.9, which costs $243.62. At these national-average prices the gas furnace is the cheapest of the three by about $23 for the month, and the heat pump would need a COP above 3.21 to match it. With an older 80% AFUE furnace, the same heat would take 167.4 therms and cost $247.75, and the heat pump would come out slightly ahead.

Monthly gas cost by usage

The table converts common monthly usage into CCF, million Btu and cost at the 2025 U.S. all-in average of $1.48 per therm. For scale, EIA's analysis of its 2020 Residential Energy Consumption Survey put average household natural gas use at 56.6 million Btu a year nationally, about 566 therms or $837.68 a year at that price, and 76.1 million Btu in the Midwest.

Furnace gas use by size and run time

Gas use is input rating times firing time. This table shows a 30-day month for a range of furnace input ratings and daily burner hours, with the cost at $1.48 per therm. Firing time depends on the weather, the house and the thermostat setting, so if your thermostat keeps a runtime history, use it.

Doubling either the rating or the hours doubles the gas, so a furnace that is larger than the house needs does not burn proportionally more fuel over a season: it fires for shorter periods. What drives the seasonal total is the heat the house loses, divided by the furnace's efficiency.

Natural gas prices by state and by season

Residential gas prices differ widely from state to state. EIA's 2025 annual averages range from $7.69 per Mcf in Idaho to $52.38 in Hawaii, against a U.S. average of $15.34. The table converts selected states to price per CCF and per therm (at 10.37 therms per Mcf) and shows what 50 therms would cost.

These are all-in averages, and EIA does not publish a 2025 figure for every state; where yours is missing, use your own bill. The price per unit also swings with the season. EIA explains that residential prices are usually highest in summer and lowest in winter because the fixed costs of delivering gas are spread over a smaller volume when households use less. The U.S. residential average was $13.96 per Mcf ($1.346 per therm) in January 2026 and $26.45 per Mcf ($2.551 per therm) in July 2026. A summer bill with a high price per therm is usually a fixed charge spread over very little gas, not a rate increase.

Gas heat vs electric resistance vs a heat pump

To compare heating fuels fairly, compare the cost of delivered heat, not the cost of the fuel. A therm holds 100,000 Btu, but a furnace only puts its AFUE share into the house. A kWh holds 3,412 Btu, which electric resistance heat delivers in full and a heat pump multiplies by its coefficient of performance (COP). DOE's federal purchasing guidance compares an 80% AFUE baseline furnace with ENERGY STAR models at 90% in southern states and 95% in northern states, and notes that the best available models reach 99%. DOE also says today's heat pumps can cut electricity use for heating by approximately 65% compared with resistance heating, which corresponds to a COP of about 2.9.

At $1.48 per therm and 18 cents per kWh, resistance heat costs more than three times as much as a 90% furnace for the same warmth. A heat pump lands close to gas: it needs a seasonal COP of 3.21 to beat a 90% furnace and 2.85 to beat an 80% one. Local prices decide it. Where gas is cheap and power is expensive the furnace wins easily, and where gas is costly and power is cheap the heat pump does.

How to use this calculator

Choose From my bill to enter the usage on your statement in therms, CCF, Mcf or cubic feet, or From an appliance to estimate one appliance's use from its input rating, its daily burner hours and the number of days. Check the therm factor on your bill and replace the 1.037 default if it differs. Enter your price and the unit it is quoted in. If you use the EIA average ($1.48 per therm or $15.34 per Mcf), leave the fixed charge at $0 because the average already includes it; if you enter your bill's itemized rates, add the fixed customer charge and the percentage for taxes and fees. The comparison card uses your furnace's AFUE, your electricity price and a heat pump COP.

The result shows the total cost, usage in therms and CCF, the energy charge and your all-in price per therm and per CCF, followed by a step-by-step breakdown and the cost of the same heat from electric resistance and a heat pump. It is meant for homeowners and renters checking a bill, households budgeting for winter, anyone sizing up the running cost of a new gas appliance, and people weighing a heat pump against a furnace replacement.

Key terms

• Btu: British thermal unit, the energy needed to warm one pound of water by one degree Fahrenheit.
• Therm: 100,000 Btu. MMBtu: one million Btu, or 10 therms.
• CCF and Mcf: 100 and 1,000 cubic feet of gas, the volume units on most meters.
• Therm factor: the therms per CCF of the gas your utility delivered, used to turn volume into billed energy.
• Input rating: the gas an appliance burns per hour while firing, in Btu per hour, printed on its rating plate.
• AFUE: annual fuel utilization efficiency, the share of a furnace's fuel that becomes heat for the home over a year.
• COP: coefficient of performance, the units of heat a heat pump delivers per unit of electricity.
• Fixed customer charge: the monthly amount billed regardless of usage, covering metering, service and delivery costs.
• Supply and delivery charges: the cost of the gas itself and the cost of moving it through pipelines to your meter.

What changes your gas bill

• Weather. Space heating dominates winter gas use, so a cold month can use several times the gas of a mild one.
• Thermostat settings. Every degree you hold the house above the outdoor temperature adds to the heat it loses and the gas the furnace burns.
• Heat content. A higher therm factor means more therms billed for the same metered volume.
• Rate structure. Fixed charges, tiers and seasonal rates make the all-in price per therm change from month to month.
• Equipment efficiency. At the same heat output, an 80% AFUE furnace burns 12.5% more gas than a 90% one.

A few habits keep the bill down: compare your all-in price per therm across months instead of the bill total, check the therm factor and meter reading on each statement, lower the thermostat while you sleep or are away, keep the furnace serviced and its filter clean, and use the appliance mode to find out which appliance uses the most gas before you replace anything.

Limitations

The calculator applies one price to every therm. Real tariffs can have tiers, seasonal rates, minimum bills and riders, and some households pay through budget billing that evens out payments over the year. The appliance estimate assumes the burner fires at its full input rating for the hours you enter; modulating and two-stage furnaces often run below full input, and standing pilot lights burn a little gas around the clock. The heating comparison ignores fixed charges, duct losses and the backup resistance heat a heat pump may use in very cold weather, and it treats COP as a single seasonal average. Use your bill and your utility's tariff sheet for exact figures.

Related calculators

• To price electric appliances and heaters by wattage, use the Electricity Cost Calculator.
• To size heating or cooling capacity for a room, use the BTU Calculator.
• For what an electric car adds to the power bill, use the EV Charging Calculator and the EV vs Gas Calculator.
• For gasoline rather than natural gas, use the Fuel Cost Calculator or the Gas Mileage Calculator.
• To fit the gas bill into monthly spending, use the Budget Calculator.

Sources

• EIA, U.S. price of natural gas delivered to residential consumers (annual): $15.34 per Mcf in 2025 and $14.50 in 2024; monthly series: $13.96 in January 2026 and $26.45 in July 2026.
• EIA, residential natural gas prices by state: 2025 annual averages.
• EIA FAQ, Ccf, Mcf, Btu and therms: 2025 average heat content of about 1,037 Btu per cubic foot; 1 Ccf = 1.037 therms.
• EIA, British thermal units: 1 therm = 100,000 Btu and 1 kWh = 3,412 Btu.
• EIA, Today in Energy (August 7, 2023): household natural gas use of 56.6 million Btu nationally and 76.1 million Btu in the Midwest (2020 RECS).
• EIA, Today in Energy (March 9, 2015): why residential prices are usually highest in summer and lowest in winter.
• EIA Electric Power Monthly, Table 5.3: U.S. residential electricity price of 17.99 cents per kWh for the 12 months through July 2026.
• DOE Federal Energy Management Program, residential furnaces: 80% baseline, 90% and 95% ENERGY STAR levels and 99% best available AFUE.
• DOE, Home Upgrades: heat pumps can reduce electricity use for heating by approximately 65% compared with resistance heating.