Carbon Offset Cost Calculator

A carbon offset represents the reduction of one metric ton of CO₂ equivalent (CO₂e) emissions from the atmosphere, used to compensate for emissions produced elsewhere.

Carbon footprint formula: Carbon Footprint (kg CO₂e) = Activity Amount × Emission Factor

Each emission factor is specific to the activity and energy source.

Common emission factors:

• Car travel (average petrol): 0.192 kg CO₂e per km
• Short-haul flight: ~0.255 kg CO₂e per km per passenger
• Long-haul flight: ~0.195 kg CO₂e per km per passenger
• Natural gas heating: 2.04 kg CO₂e per cubic meter
• Electricity (US average grid): 0.386 kg CO₂e per kWh
• Beef consumption: ~27 kg CO₂e per kg of beef

Worked example, annual driving: You drive 15,000 km per year in a petrol car. Annual Emissions = 15,000 × 0.192 = 2,880 kg CO₂e = 2.88 tonnes CO₂e

Offset cost at $15/tonne: $43.20/year

Round-trip flight example: New York to London is about 5,540 km each way, so a return trip is ~11,080 km. That is a long-haul route, which carries the lower per-km factor: 11,080 × 0.195 = 2,161 kg CO₂e = 2.16 tonnes. Offset cost at $15–$25/tonne: $32–$54.

Two traps live in that one line, and this page used to fall into both. The 11,000 km figure is already the round trip, so multiplying it by two again doubles the flight. And 0.255 is the short-haul factor. Long flights burn proportionally less per kilometre because the fuel-hungry climb is amortised over a much longer cruise, which is why the factor drops to 0.195. Using the wrong one on a transatlantic return overstates it by about 30% before the doubling error even lands.

The prices written above are US dollars. The calculator follows whichever currency you have chosen in the header, but it swaps the symbol rather than converting the rate, so enter a price you have actually been quoted in that currency.

Average annual carbon footprint by country (tonnes CO₂e/person):

• USA: ~14–16 tonnes
• UK: ~5–6 tonnes
• Germany: ~8–9 tonnes
• India: ~2 tonnes
• World average: ~4.7 tonnes

Quality note on offsets: Carbon offsets vary enormously in quality. Look for projects certified by Gold Standard or Verra (VCS) for verified, permanent, and additional emissions reductions.

Working out your own tonnage

Leave the emissions box empty and fill in whichever activity lines apply, and the page adds them up using the factors listed above. It is not a full footprint. Food beyond beef, everything you buy, and your share of public infrastructure are all missing, and together those usually outweigh the lines here. Treat the total as the part of your footprint you directly control, then compare it against the country averages to see how much is unaccounted for.