Natural Gas Bill Calculator
This tool helps you rebuild a gas bill one line at a time. Enter therms or Ccf. Then add the gas supply cost, delivery rate, monthly charge, riders, credits, and tax.
1Enter usage from the meter or bill
Use the factor on your bill. EIA reported 1.037 as the 2025 U.S. average.
2Rebuild the charges
Estimated gas bill
$127.72
80.0 therms at a full cost of $1.60 per therm.
Gas supply
$60.00
Variable delivery
$44.00
Fixed + riders
$20.00
Taxes
$3.72
Your rate plan may include seasonal prices, weather adjustments, special riders, minimum bills, city taxes, and charges from another gas seller. For a close estimate, enter every charge shown on the current bill or rate plan.
Inputs stay in this browser. No account or quote request is required.
Quick planning answer
A gas bill is usually more than therms times one rate. It may include gas supply, delivery per therm, a monthly customer charge, riders, and taxes. Divide the final bill by therms to find the full cost per therm for comparison.
Ccf measures volume, while therms measure energy
Gas meters often track hundreds of cubic feet, or Ccf. The utility uses a heat-content factor to change that volume into therms. EIA reported that 1 Ccf was about 1.037 therms using the 2025 U.S. average. Use the factor on your own bill because gas heat content and billing conditions vary.
Some bills include a pressure factor or show the change from Ccf to therms on several lines. Enter the final therms-per-Ccf factor from the bill instead of rebuilding the utility's meter adjustment.
Fixed fees can make summer gas look costly
A $20 customer charge spread across 10 summer therms adds $2 per therm before supply and delivery. The same fee spread across 150 winter therms adds about 13 cents per therm. This is why the full monthly rate can rise even when the price of gas falls.
- Compare bills with the same number of days when possible.
- Keep supply and delivery separate when another gas seller appears on the bill.
- Enter credits as negative riders and extra charges as positive riders.
- Use therms, not dollars, to judge whether home improvements lowered gas use.
Two bills are not enough to adjust for weather
A colder month may use more gas even after an energy-saving project. The home may still be more efficient. For a fair comparison, subtract the normal summer use for water heating, cooking, and drying. Then compare heating use per heating degree day.
Budget plans spread payments across the year, but they do not lower the yearly cost. Check the plan balance, 12 months of actual therm use, and every rate line before comparing fuels or project payback.
Questions people ask before buying
How do I calculate my natural gas bill?
Change usage to therms. Multiply therms by the supply and delivery rates. Add fixed charges and riders. Then add the taxes required by the rate plan.
How many therms are in one Ccf?
It changes with the heat content of the gas. Using EIA's 2025 U.S. average, 1 Ccf was about 1.037 therms. Use the factor printed on your utility bill.
Why is my effective gas rate higher in summer?
The fixed monthly charge is spread across fewer therms. Even with the same rates, the full cost per therm can be much higher in a low-use month.
What is a gas bill rider?
A rider is an extra charge or credit on the utility rate. It may cover gas-price changes, infrastructure, efficiency programs, weather adjustments, or other approved costs.
Method, sources and limits
When you enter Ccf, the tool multiplies it by the therm factor. Therm entries need no change. The tool multiplies therms by both the supply and delivery rates. It adds fixed charges and positive or negative riders before applying the tax percentage.
The full rate per therm equals the final bill divided by therms. The tool does not include utility-specific seasonal rates, minimum bills, usage tiers, pressure corrections, or special tax rules unless you can enter them in the fields.
- Natural gas price components (U.S. Energy Information Administration)
- Converting cubic feet and therm prices (U.S. Energy Information Administration)
- Natural gas customer-choice billing (U.S. Energy Information Administration)