Carbon Footprint Offset Calculator

This calculator adds up four everyday sources of household carbon emissions using fixed per-unit factors rather than a full lifecycle analysis. Electricity is converted at the US grid average of 0.417 kg CO₂ per kWh, close to the 0.394 kg/kWh eGRID2022-derived national average EPA's own Greenhouse Gas Equivalencies Calculator uses, so your actual footprint will be lower on a cleaner regional grid and higher on a coal-heavy one. Driving uses 0.404 kg CO₂ per mile, close to the EPA calculator's 0.393 kg/mile average passenger-vehicle figure, so a hybrid or EV owner will overstate their footprint here and a truck or SUV owner will understate it.

Flights assume a flat 2,000-mile round trip per flight entered at 0.255 kg CO₂ per passenger-mile, meaning a short regional hop and a transatlantic flight are treated identically — enter more or fewer "flights" to approximate longer or shorter trips. Diet is handled as a fixed annual figure by category (vegan ≈1.5 tons, vegetarian ≈1.7, average omnivore ≈2.5, heavy meat ≈3.3) rather than scaled to your actual food choices, since diet's carbon footprint is dominated by meat and dairy production rather than easily itemized per meal. The four totals sum to your annual footprint in metric tons, which then converts to trees needed (at 60 kg CO₂ absorbed per tree per year, EPA's estimate for a medium-growth urban tree over its first 10 years) and a rough offset-purchase cost at $25/ton — a mid-range price; real voluntary carbon offsets can run anywhere from $15 to $50+ per ton depending on the project type and verification standard.