Turn fuel use into tonnes of CO2 and price it at any carbon price. At $50/tonne, a gallon of gasoline carries about 44.4¢ of carbon cost — roughly 10.9% of the current $4.085 pump price. Figures are EPA tailpipe factors; well-to-wheel emissions run 15–25% higher.
Volume × emission factor × carbon price.
Formula: tonnes CO₂ = quantity × kg-per-unit ÷ 1,000; carbon cost = tonnes × price. EPA tailpipe factors: gasoline 8.887 kg/gal, diesel 10.180, heating oil 10.210, jet 9.750, propane 5.720, natural gas 5.302 kg/therm.
What the same fuel costs across the range real schemes use.
Benchmarks for scale: California allowances have generally traded around $30–$40, the EU ETS roughly €60–€90, and Canada's federal charge was legislated toward C$170 by 2030. None of these necessarily applies to the fuel you have entered — coverage differs by scheme.
About 8.887 kg — near enough 19.6 pounds. That surprises people because a gallon of petrol weighs only about 6.3 pounds. The extra mass is oxygen: burning pulls O2 out of the air and each carbon atom leaves as CO2, which is substantially heavier than the carbon that went in. Diesel is higher at 10.18 kg per gallon because it is denser and more carbon-rich.
It varies enormously by jurisdiction. The EU Emissions Trading System has traded broadly in the €60–€90 range, Canada's federal carbon charge was legislated on a rising path toward C$170 by 2030, and California allowances have generally sat in the $30–$40 band. Many economists' estimates of the social cost of carbon are considerably higher than any of these. There is no single right number, which is why this calculator lets you set it.
No. These are tailpipe (combustion) emissions only. A full well-to-wheel accounting adds the energy used to extract, refine and transport the fuel, plus methane leaking from production and pipelines — typically another 15 to 25% on top for petroleum fuels, and potentially far more for gas where leakage is high. Methane is a much stronger greenhouse gas than CO2 over a twenty-year horizon, so the gap is sensitive to how leakage is counted.
Only if it applied to transport fuels and were passed through in full, and many carbon-pricing schemes deliberately do not cover them or return revenue to households. This calculator shows the gross arithmetic — the carbon content of the fuel at your chosen price — not a forecast of any particular policy.