Natural Gas vs Propane Cost Calculator

How to do it

1. 1
   Step 1: Open Natural Gas vs Propane Cost Calculator and add your input

   Type your numbers or text, add your file, or pick the options you need. Nothing is uploaded: everything stays in your browser.

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   Step 2: What Natural Gas vs Propane Cost Calculator does

   Compare the cost per million BTU of natural gas and propane.

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   Step 3: Read the result and compare

   The result appears at once. Change one value to see how the answer moves, then keep the figure that fits your case.

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   Step 4: Copy or save it

   Copy the result or download it. For an important decision, confirm it with the official source or an adviser.

About this tool

Enter the price of natural gas per therm and of propane per gallon and the appliance efficiency. The calculator converts both to a cost per million BTU and shows which is cheaper and by how much.

Energy content

One therm of natural gas is 100,000 BTU, so one million BTU is 10 therms. One gallon of propane has about 91,500 BTU, so it takes about 10.9 gallons for a million BTU.

Cost per million BTU

Cost per MMBtu = price per therm × 10 ÷ efficiency for natural gas, and price per gallon ÷ 0.0915 ÷ efficiency for propane. Compare them on the same basis.

Note

Propane needs a tank and delivery or exchange; natural gas needs a pipeline connection. Fixed charges are not included.

Worked example

Natural gas at $1.35 a therm and propane at $2.80 a gallon, both burned at 92%: natural gas costs $14.67 per million BTU and propane $33.26, so natural gas is about $18.59 cheaper.

Tips for best results

Check every box before you rely on a result, because one wrong digit changes the whole answer. Use the exact figures from your payslip, bill, certificate or contract, and keep a note of the date you calculated. Rates, thresholds and rules change from time to time, so for tax, fees and legal matters treat the output as an estimate and confirm with the official source named on this page. You can run as many scenarios as you like; nothing is saved or sent, and refreshing the page clears the boxes.