About FatGas.com

FatGas.com is an independent, advertising-supported site built around six free calculators for climate and energy questions — along with climate guides and a Climate & Earth Museum — for anyone trying to put a number on a carbon footprint, a flight, an EV, a power bill, a rooftop solar quote, or a carbon offset.

How the calculators are built

Every tool works the same way: it takes a few real-world numbers you enter — miles driven, kilowatt-hours used, a flight’s distance, a system’s size — and multiplies them by a documented emission factor or physical constant. Nothing is looked up from a database of your specific car, meter, or flight; the factors are fixed averages built into the calculator.

The Carbon Footprint Calculator adds up home electricity at 0.417 kg CO2 per kWh, natural gas at 5.3 kg per therm, driving at 0.404 kg per mile, a flat 250 kg for a short-haul flight and 1,100 kg for a long-haul one, and a yearly diet baseline that runs from roughly 1,500 kg for a vegan diet up to 3,300 kg for a heavy-meat one — summed into an annual total, in kilograms and tonnes of CO2e, with a per-day figure alongside it.

The Flight Emissions Calculator multiplies distance by 0.115 kg CO2 per passenger-kilometre, an average intensity for a typical jet, doubles it for a return trip, and applies a cabin-class multiplier — 1× economy, 1.6× premium economy, 2.9× business, 4× first. It reports direct CO2 only; it does not add the roughly 1.9× non-CO2 warming effect from contrails and high-altitude emissions, so treat the number as a conservative one.

The EV Savings Calculator works out a gas car’s annual fuel cost and emissions from your yearly miles, its MPG, your fuel price, and 8.89 kg CO2 per gallon burned, then works out the EV side from the same miles, the vehicle’s efficiency in miles per kWh, your electricity price, and the grid carbon intensity you enter. The difference between the two is the savings shown.

The Home Energy Calculator multiplies your monthly electricity use by 12 for an annual kilowatt-hour figure, applies your rate for a yearly cost, and multiplies that usage by a grid carbon intensity (kg CO2 per kWh) you supply to estimate annual emissions.

The Solar Savings Calculator multiplies a system’s size in kilowatts by your average peak sun hours per day and by 365 days to estimate annual production, then turns that into bill savings at your electricity rate, a simple payback period against your install cost, and CO2 avoided at your grid’s carbon intensity, projected over a 25-year system life.

The Carbon Offset Calculator takes a quantity of CO2 and divides it by 21 kg — roughly what a mature tree absorbs in a year — to estimate trees needed, multiplies your tonnes by a price per tonne for a cost, and divides by 0.404 kg per mile to show the equivalent distance of average-car driving.

Where the numbers come from

The emission factors above are widely-cited averages — the kind published for household electricity, vehicle fuel, and jet fuel burn — not a measurement of your specific meter, car, or flight. Your actual footprint depends on your local grid mix, your vehicle, how your food and goods are produced, and dozens of other details a simple calculator cannot see. Treat every result here as a planning estimate for comparing choices and tracking a rough direction, not a certified carbon audit. This site is not affiliated with the EPA, the IPCC, any utility, automaker, or solar installer, and none of this is professional environmental, financial, or engineering advice — for figures that need to hold up to scrutiny, check them against the EPA, the IPCC, or your own utility and installer.

What this is — and isn’t

Beyond the calculators, the site carries climate articles and guides on greenhouse gases, energy, and emissions, plus a Climate & Earth Museumwhose entries, images, and facts are drawn from Wikipedia and Wikimedia Commons rather than written in-house. FatGas.com runs on advertising, has no staff directory, no founding story, and does not collect or sell your data. What it is: six calculators built on published, named methods, and a set of guides and a museum gallery to go with them. What it isn’t: a scientific body, a certification service, or a substitute for professional advice.

Found a number that looks off, or have a tool you wish existed? See Contact.