Natural Gas Cost Calculator

Frequently Asked Questions

What is a therm?

A therm is a unit of heat energy equal to exactly 100,000 BTU. It is the standard billing unit for natural gas in the United States. One therm is roughly equal to 100 cubic feet (1 ccf) of gas.

What is the difference between ccf and therm?

ccf is a volume unit (100 cubic feet); therm is an energy unit. They differ by the heating content of the gas, typically 1.037 therms per ccf. Check your bill for the conversion factor used by your utility.

Why is my actual bill different from this estimate?

Bills include tiered rate blocks, demand charges, taxes, and delivery riders not modeled here. Add other riders to the fixed charge field as an approximation.

How do I find my price per therm?

Look for supply and delivery charges on your gas bill - in deregulated markets these may be separate line items. Add them for the total per-therm cost.

Provided by AllCalculators.io
Free online calculators for everyday. No registration required.

Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

JavaScript is required to use the interactive calculator above. The questions and answers below remain readable without JavaScript.

How It Works

Natural gas is billed by energy content, not raw volume. The anchor unit is the therm, defined as exactly 100,000 BTU. Utilities meter volume in ccf (hundred cubic feet) and convert using a heating value, typically about 1.037 therms per ccf. Your bill is: Cost = (therms used × price per therm) + fixed monthly service charge.

For appliance estimates, the tool works in reverse: an appliance rated in BTU/hr, run for a number of hours over a number of days, consumes (BTU/hr × hours × days) ÷ 100,000 therms. Metric meters report cubic metres (1 m³ ≈ 36,303 BTU).

Worked Example

A furnace rated 60,000 BTU/hr running 5 hours/day for 30 days: 60,000 × 5 × 30 = 9,000,000 BTU = 90 therms. At $1.20/therm that is $108.00 of gas, plus a $12 fixed charge = $120.00 for the month. Converting 90 therms: 90 ÷ 1.037 ≈ 86.8 ccf, or about 247.9 m³. A cold snap doubling furnace runtime roughly doubles the variable part of the bill but leaves the fixed charge unchanged.

Comparing Gas to Electric Heat

To compare natural gas and electricity on a cost-per-heat basis, you must account for equipment efficiency. One therm = 29.3 kWh of energy, but a gas furnace at 80-95% AFUE delivers 80-95% of that to the space. An electric heat pump at 250-400% effective efficiency (COP 2.5-4.0) delivers 250-400% of each kWh consumed. This means a heat pump can be cheaper to run even when electricity costs more per kWh than gas - compare delivered BTUs per dollar, not raw energy per dollar.

FAQ

What is a therm?

A therm is a unit of heat energy equal to exactly 100,000 BTU. It is the standard billing unit for natural gas in the United States. One therm is roughly equal to 100 cubic feet (1 ccf) of gas, depending on local heating content.

What is the difference between ccf and therm?

ccf is a volume unit (100 cubic feet); therm is an energy unit. They differ by the heating content of the gas, typically 1.037 therms per ccf. Your local factor may vary slightly - check your bill for the conversion factor used.

Why is my actual bill different from this estimate?

Bills include fixed service charges, tiered or seasonal rate blocks, demand charges, taxes, and delivery riders. This calculator models the energy charge and fixed charge only. Add other riders to the fixed charge field as an approximation.

How do I find my price per therm?

Look for the supply and delivery charges on your gas bill - in deregulated markets these may be separate line items. Add them for the total per-therm cost.

Natural Gas Cost Calculator

Frequently Asked Questions

Related Energy & Utilities Calculators