Carbon Footprint Calculator

What is your household's carbon footprint? Enter energy use and travel — get a full CO2 breakdown with solar offset potential.

Household energy use (annual)

Electricity use?

kWh/yr

Grid emission factor?

Natural gas use?

therms/yr

Car miles driven?

mi/yr

Flights per year?

flights

Solar production (if any)?

kWh/yr

Total household carbon footprint

11.4 tons CO2/year

Electricity1.9 tons

Natural gas0.4 tons

Driving6.1 tons

Flights3.0 tons

Solar could offset your electricity footprint with a 7.6 kW system. That would eliminate 1.9 tons/year (17% of your total footprint).

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How to Use This Calculator

Enter your electricity use

Input your annual electricity consumption in kWh. Find this on your utility bills — most utilities show a 12-month usage history. The US average household uses about 10,800 kWh/year. Also select your grid emission factor to match your region's electricity mix.

Add natural gas consumption

Enter annual natural gas use in therms. Check your gas utility bills — they show therms consumed each month. The US average home uses about 78 therms/year for heating and appliances. If you have all-electric heat and appliances, enter 0.

Enter driving miles

Input the total miles driven per year across all household vehicles. The US average is about 15,000 miles per driver. If you have an EV, its emissions are already partially captured in your electricity figure, so count the miles you actually drove (the electricity use for EV charging is included in your kWh figure).

Count your flights

Enter the number of round-trip flights per year. This calculator uses ~1.5 metric tons CO2 per average round trip, which accounts for both fuel burn and high-altitude radiative forcing effects.

See your solar offset potential

Expand "Solar offset" to enter your existing solar production, or use the recommendation in the results to see what system size would fully offset your electricity footprint.

The Formula

Electricity CO2 = Annual kWh × Grid emission factor (lbs/kWh) Natural gas CO2 = Annual therms × 11.7 lbs CO2/therm Car CO2 = Annual miles × 0.891 lbs CO2/mile Flight CO2 = Flights × 3,307 lbs CO2/round trip Total CO2 (tons) = Sum of all sources ÷ 2,204.62 Solar offset = Solar kWh × Emission factor ÷ 2,204.62 Net footprint = Total CO2 − Solar offset

Emission factors: Natural gas at 11.7 lbs CO2/therm is the EPA standard. Car emissions at 0.891 lbs/mile assumes the US average light vehicle fleet. Flight emissions at ~1.5 metric tons/round trip is a mid-range estimate that includes a 1.9x radiative forcing multiplier for high-altitude effects.

Example

The Williams household — Indianapolis, IN

Two-adult household with one car, modest travel habits, and gas heating. Indiana has a relatively carbon-intensive grid (~0.56 lbs/kWh).

Electricity11,500 kWh/yr

Grid emission factor0.56 lbs/kWh

Natural gas95 therms/yr

Car miles18,000 mi/yr

Flights2 round trips/yr

Result

Electricity2.92 tons CO2

Natural gas0.50 tons CO2

Driving7.27 tons CO2

Flights3.00 tons CO2

Total13.7 tons CO2/year

A 5.2 kW solar system would fully offset their electricity footprint (2.92 tons), reducing their total footprint by 21%. To tackle driving emissions, an EV charged by solar would be the next highest-impact step.

FAQ

What is the average US household carbon footprint? ▼

The average US household emits about 48 metric tons of CO2 equivalent per year when counting all sources including food, purchases, and services — not just energy and transportation. For home energy and transportation only (what this calculator covers), the typical range is 10-20 tons/year. The global average per capita is about 4-5 tons/year, making the US one of the highest-emitting countries per household.

Which source contributes most to household carbon footprint? ▼

For most US households, transportation (driving + flying) is the largest single category, often representing 40-60% of the energy-and-transport footprint. Home electricity and heating together typically account for 30-40%. This is why solar + EV is such a powerful combination — it attacks both major categories simultaneously.

How much does solar reduce your carbon footprint? ▼

A typical 8-10 kW residential system offsets 2-4 tons of CO2/year, depending on location and grid intensity. This typically reduces a household's energy-and-transport carbon footprint by 15-30%. If you also switch to an EV charged by solar, you can reduce total transportation emissions by 50-80%, bringing combined savings to 40-60% of your baseline footprint.

Are flight emissions really that high? ▼

Yes — air travel is one of the most carbon-intensive activities per hour. This calculator uses ~1.5 metric tons CO2 per average round trip, which includes a radiative forcing multiplier (because emissions at altitude have roughly 2x the warming effect of the same emissions at ground level). A long-haul international round trip (US to Europe) can emit 2-3 metric tons. Even short domestic flights (~1,000 miles round trip) emit about 0.5-0.8 metric tons. Reducing flying is one of the highest-impact personal climate actions available.

What isn't included in this calculator? ▼

This calculator covers home energy (electricity + gas) and transportation (driving + flying). It doesn't include: food consumption (beef is particularly high-carbon), purchased goods and services, heating oil or propane, public transit, or industrial/commercial emissions allocated to households. A full lifecycle footprint calculator would typically show 2-3x higher numbers when including embedded carbon in food and consumer goods.