Gasoline to CO2 Converter
| Gallons | Gasoline kg CO2 | Diesel kg CO2 |
|---|---|---|
| 1 | 8.89 | 10.18 |
| 5 | 44.44 | 50.90 |
| 10 | 88.87 | 101.80 |
| 20 | 177.74 | 203.60 |
Every gallon of gasoline burned sends exactly 8,887 grams of CO2 out the tailpipe - the EPA's own emission factor, measured and published for the whole US fleet. Diesel is heavier at 10,180 grams per gallon, which surprises people until they remember diesel is denser: per gallon diesel emits more, but per mile a diesel car usually emits less because it goes farther on that gallon.
Type gallons from any receipt, tank size or trip and the converter gives the carbon in kilograms and pounds, plus the driving equivalent - how far the average passenger vehicle would have to drive to release the same CO2 at its typical 400 grams per mile. The three numbers move together because they come from the same EPA ledger that powers the federal greenhouse-gas equivalencies calculator.
How to use
- Type gallons from a fill-up receipt or a tank size, pick the fuel, and read the CO2 in kilograms and pounds.
- The driving-equivalent line translates carbon back into distance: how far an average car drives to emit the same.
- Annual math: a car driven 11,500 miles a year burns roughly 460 gallons - about 4.1 tonnes of CO2 - close to the EPA's 4.6-tonne fleet average.
Frequently asked questions
How much CO2 is in a gallon of gasoline?
8,887 grams - about 8.9 kilograms or 19.6 pounds - the EPA's standard emission factor for a US gallon of gasoline. It is a chemical constant as much as a policy number: gasoline is roughly 87 percent carbon by mass, and burning joins each carbon atom with two oxygens, so the exhaust weighs far more than the fuel poured in.
Why does diesel emit more per gallon?
Diesel fuel is denser and carbon-richer: 10,180 grams of CO2 per gallon against gasoline's 8,887. Per mile the picture flips - diesel engines squeeze more work from each gallon, so a diesel car's per-mile CO2 is often lower than a comparable gasoline car's. Compare per gallon and diesel looks worse; compare per mile and the answer depends on the vehicle, which is why the EPA publishes both factors.
Does the factor include refining and drilling?
No - 8,887 grams is what comes out of the tailpipe, the combustion only. The full lifecycle adds roughly another 20 to 25 percent upstream: drilling, shipping, refining and the electricity the pump uses. Lifecycle accounting is the right lens for policy; tailpipe accounting is the right lens for your tank, and this converter runs the tailpipe factor.
How many trees would absorb my fill-up?
A young tree sequesters on the order of 20 to 25 kilograms of CO2 per year once established, so one 12-gallon fill-up (about 107 kilograms of CO2) is several tree-years of work. That asymmetry - seconds to emit, years to absorb - is the whole arithmetic problem with offsetting, and why efficiency beats offsets in every serious comparison.
Where do these exact numbers come from?
The EPA's Greenhouse Gas Emissions from a Typical Passenger Vehicle page publishes the factors this converter runs: 8,887 grams of CO2 per gallon of gasoline, 10,180 for diesel, about 400 grams per mile for the average passenger vehicle, and 4.6 metric tons a year. They are the same factors behind the federal equivalencies calculator, so the numbers here match what agencies quote.