What emission factors does this tool use?

Electricity uses the US average grid factor of 0.386 kg CO2e per kWh (US EPA eGRID 2023). Natural gas uses 5.3 kg CO2e per therm. Gasoline combustion uses 8.887 kg CO2e per gallon (US EPA). Short-haul flights use 0.255 kg CO2e per passenger-km and long-haul use 0.195 kg CO2e per passenger-km (ICAO 2023), with a 1.9× radiative forcing multiplier applied.

What is CO2e (CO2-equivalent)?

CO2e bundles all greenhouse gases — carbon dioxide, methane, nitrous oxide, and others — into one number by converting each gas to the amount of CO2 that would have the same warming effect over 100 years. This makes it easy to compare different emission sources on a single scale.

How accurate are these estimates?

This tool gives a reasonable order-of-magnitude estimate for US-based households. Actual figures vary by your utility's energy mix, vehicle type, flight route, and other factors. For a precise audit, contact a certified carbon accounting firm.

What does a carbon offset cost?

Verified carbon credits on reputable registries (Gold Standard, Verra VCS) typically trade between $10 and $50 per tonne of CO2e as of 2024. This tool shows both ends of that range so you can gauge rough offset costs for your footprint.

Does this include food or consumer goods emissions?

No. This calculator focuses on the four highest-impact and most measurable categories: home energy, driving, and air travel. Food, goods, and services are significant but require detailed spending data to estimate accurately.

Carbon Footprint Calculator

Name: Carbon Footprint Calculator
Availability: InStock
Author: Nham Vu

Enter your household energy use, driving, and flight data to see your annual CO2 footprint with a breakdown chart and offset cost estimates.

Your Annual Activity

Electricity

kWh/mo

Average US household: ~900 kWh/month

Natural Gas

therms/mo

Average US household: ~50 therms/month

Vehicle Driving

Miles/year

Fuel efficiency (MPG)

Flights per Year

Short-haul (<3 hrs)

Long-haul (≥3 hrs)

Fill in your activity data and click Calculate

Summary

Enter your household energy use, driving, and flight data to see your annual CO2 footprint with a breakdown chart and offset cost estimates.

How it works

Enter your monthly electricity consumption in kilowatt-hours (check your utility bill).
Enter your monthly natural gas use in therms, or leave it at 0 if you use another heating source.
Enter the total miles you drive per year and your vehicle's average fuel efficiency in MPG.
Enter the number of short-haul and long-haul flights you take per year.
Click "Calculate" to see your total annual CO2e in kilograms and tonnes.
Review the pie chart breakdown and the suggested carbon offset cost range.

Use cases

Understand your personal or household contribution to greenhouse gas emissions.
Identify which lifestyle area — energy, driving, or flying — has the biggest impact.
Set a baseline before switching to an electric vehicle or renewable energy plan.
Estimate how much you would spend to become carbon-neutral through offset purchases.
Use the data to plan meaningful emission reductions before buying offsets.
Share results with a sustainability team or school project.
Compare before-and-after footprints when making eco-friendly life changes.
Quickly demonstrate emission concepts to clients or students.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu