Calculate natural gas cost per therm from your bill, estimate a gas bill from therms or CCF, or find usage, with fixed charges and $/kWh equivalents.

Gas volumes (CCF, MCF, ft³, m³) use a typical 1,037 Btu per ft³ (U.S. average, EIA). Your bill’s therm factor may differ.

Optional settings
Blank means zero; separate only charges unrelated to energy use.

Blank omits normalization. Daily usage and charges are assumed constant for projections.

Cost Per Therm Formula

The following equation is used to calculate the Cost Per Therm.

CPTH = (TC - F) / E
  • Where CPTH is the cost per therm ($/therm)
  • TC is the total gas bill and F is the fixed charges included in it ($)
  • E is billed energy in U.S. therms
  • For a volume reading, choose CCF, MCF, ft³ or m³; the calculator uses a typical 1.037 therms per CCF, so enter therms from your bill when you have them.

Subtract included fixed charges from the total bill, then divide the remaining energy charge by billed therms.

What is a Cost Per Therm?

Definition:

Cost per therm is the price you pay per therm of energy, which is most commonly used for natural gas billing.

This calculator uses the U.S. therm, equal to 105.4804 MJ (about 29.300111 kWh). It is not a fixed volume of gas. Your bill’s heating factor gives the exact conversion from cubic feet to therms; the calculator’s 1.037 therms per CCF is a typical U.S. value.

How to Calculate Cost Per Therm?

Example Problem:

The following example outlines the steps and information needed to calculate Cost Per Therm.

First, determine the total cost of the natural gas. In this example, the total cost is $1250.00.

Next, obtain billed energy. This example uses 20.76 U.S. therms and assumes no fixed charges.

Finally, calculate the cost per therm using the formula above:

CPTH = (TC − F) / E

CPTH = ($1250 − $0) / 20.76

CPTH = $1250 / 20.76

CPTH ≈ $60.21/therm