How to calculate your natural gas bill
- Find your usage in therms. If your bill or meter shows CCF, multiply by the heat-content factor (≈ 1.037).
- Multiply by your price per therm — supply plus delivery charges.
- Add the fixed customer charge. 60 therms × $1.50 + $12.00 ≈ $102.00.
Bill = Therms × Price per therm + Fixed charge
Example gas bills
At an example $1.50 per therm and a $12.00 monthly customer charge. Your utility's prices will differ.
| Gas used | Monthly bill | All-in per therm |
|---|---|---|
| 20 therms | $42.00 | $2.10 |
| 50 therms | $87.00 | $1.74 |
| 100 therms | $162.00 | $1.62 |
| 150 therms | $237.00 | $1.58 |
Ways to lower your gas bill
- Lower the thermostat at night and when you're away — a smart thermostat makes it automatic.
- Set the water heater to 120°F and insulate exposed hot water pipes.
- Have the furnace serviced and change filters so it runs efficiently.
- Seal drafts around doors, windows and the attic hatch.
Frequently asked questions
What is a therm?
A therm is a unit of heat energy equal to 100,000 BTU. Most U.S. gas utilities bill by the therm because it measures the energy you actually received, not just the volume of gas.
How do I convert CCF to therms?
Multiply CCF by the heat-content factor printed on your bill. It's usually close to 1.037, so 58 CCF is about 60.1 therms.
How do I calculate gas use from my meter?
Subtract last month's reading from this month's. If your meter went from 1258.4 to 1316.4 CCF, you used 58.0 CCF — about 60.1 therms.
Why is my gas bill high even when I barely use gas?
Most utilities charge a fixed monthly customer charge for keeping you connected, whether you use gas or not. In summer, when you might only run a water heater or stove, that charge can be most of the bill.
What price per therm should I use?
Add up the per-therm charges on your bill — gas supply (or commodity), delivery or distribution, and any per-therm riders. Prices vary widely by utility and change through the year, so your own bill is the best source.
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