Gas vs Electric Cost Comparison
Compare the annual running cost and CO2 emissions of gas vs electric usage — enter your gas usage (therms or kWh) and electric usage (kWh) with their prices, and see which fuel is cheaper and cleaner.
Input
Output
| Metric | Gas | Electric |
|---|---|---|
| No data yet | ||
Guides
What does this tool calculate?
Enter your annual gas usage and price, and your annual electric usage and price, and this tool works out the yearly running cost and CO2 emissions for each fuel — side by side, plus a plain-English summary of which one is cheaper and which one is cleaner. Useful for comparing gas vs electric heating, water heating, cooking, or drying, or just sanity-checking a utility bill.
How the numbers are calculated
Cost is simply usage × price for each fuel — no surprises there. Gas usage can be entered in therms (the standard US billing unit) or kWh (how gas is billed in the UK and much of the EU); pick whichever matches your bill.
CO2 emissions are estimated from each fuel's energy content using standard combustion/grid emission factors:
- Natural gas: 0.181 kg CO2 per kWh of energy content (from the EPA's 53.06 kg CO2 per MMBtu combustion factor). Therms are converted to kWh first (1 therm = 29.3001 kWh) before applying this factor.
- Electricity: 0.417 kg CO2 per kWh — a global-average grid emissions factor. Your local grid mix (more or less renewable/nuclear generation) will shift this up or down; use your utility's own published factor if you have it for a more precise number.
How to use it
- Enter your annual gas usage and pick the gas unit that matches your bill (therms or kWh).
- Enter your gas price per unit.
- Enter your annual electric usage in kWh and your electric price per kWh.
- Read the cost and CO2 comparison table, and the summary line for which fuel wins on cost and on emissions.
Frequently asked questions
Why is electricity's CO2 factor higher even though gas burns fossil fuel directly? It depends heavily on your grid's generation mix. A grid running mostly on coal will emit far more CO2 per kWh than natural gas combustion; a grid running mostly on renewables/nuclear will emit far less. The 0.417 figure here is a global average — swap in your own utility's published emissions factor for an accurate local comparison.
This doesn't account for appliance efficiency — should it? No, deliberately — this tool compares fuel cost and emissions on a straight usage basis. A heat pump moving 3 kWh of heat per 1 kWh of electricity and a gas furnace running at 95% combustion efficiency use very different amounts of raw energy for the same comfort level; enter each appliance's actual metered usage (from a bill or a manufacturer's spec) rather than assuming they're equivalent.
Where do the 0.181 and 0.417 kg CO2/kWh figures come from? The gas factor is the EPA's published natural gas combustion emissions factor, converted from kg CO2 per MMBtu to kg CO2 per kWh. The electricity factor is the same global-average grid factor used elsewhere on this site (see the electricity cost calculator).
Privacy
All calculations run locally in your browser. No usage figures or prices are sent anywhere.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/gas-vs-electric-cost-comparison \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"gasUsage": "500",
"gasUnit": "therms",
"gasRateTherm": "1.20",
"gasRateKwh": "0.06",
"electricUsage": "10000",
"electricRate": "0.16"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `gas-vs-electric-cost-comparison` tool (Gas vs Electric Cost Comparison) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.