Household Carbon Footprint Calculator

How the footprint is calculated

The estimate is built in four blocks and the emissions factors are stated here in full, because they are the whole calculation. Electricity: your monthly bill is divided by 0.16 dollars to get kilowatt-hours, multiplied by 0.92 pounds of carbon dioxide per kilowatt-hour and by twelve, then converted to tons. Solar on the roof multiplies that result by 0.7. Natural gas: the bill is divided by 1.50 dollars a therm and each therm is charged 11.7 pounds. Heating oil is 22.4 pounds a gallon. Driving assumes 25 miles per gallon for a petrol car and 45 for a hybrid, at 19.6 pounds a gallon, while an electric car is charged 0.3 kilowatt-hours a mile at the same grid factor as the house. Flights are flat: half a ton for a short one, one and a half for a long one.

Two of those factors are the Environmental Protection Agency's published equivalency figures exactly — 11.7 pounds a therm is their 0.0053 metric tons, and 19.6 pounds a gallon of petrol is their 8,887 grams. The 22.4 pounds a gallon for heating oil sits just under their distillate figure of 431.87 kilograms per 42-gallon barrel, which works out at 22.7 pounds. The grid factor of 0.92 pounds a kilowatt-hour is an older national average and now runs above their current one for electricity used, 3.94 × 10⁻⁴ metric tons, which is about 0.87 pounds. The electricity price of 0.16 dollars a kilowatt-hour and the gas price of 1.50 dollars a therm are ours, and if your rate is different your energy figure is wrong in proportion.

Diet and waste are per-person estimates of our own with no published factor behind them: 3.3 tons a year for daily meat down to 1.5 for none, multiplied by 1.3 for high food waste down to 0.75 for minimal, then by the number of people. Waste runs 0.8 to 1.5 tons a person by recycling habit, times 0.8 if you compost. The comparison bars use 48 tons for a United States household and 4.8 tons a person globally — round figures we ship rather than a series we can point you at, because the two sources we tried to check them against would not answer an automated request.

The tree count is the softest number on the page. It divides your total by 48 pounds of carbon dioxide a year per tree, which is a common rule of thumb and well below the EPA's own 0.06 metric tons — about 132 pounds — for an urban tree planted and grown for ten years. Read the trees as a picture of the size of the number, not as an offset you could buy.

Where these numbers come from

1. 1. Greenhouse Gases Equivalencies Calculator — Calculations and References — U.S. Environmental Protection Agency

Every figure above was read out of the code that runs on this page. Where a number is our own judgement rather than a published one, the note says so and cites nothing. Method last checked 21 August 2026.