Yearly CO2 from your car - fuel-type aware, with EV grid factor and carpool sharing.
Tank-to-Wheel CO₂ factors (ADEME 2024): petrol 2.31, diesel 2.69, E85 1.6, LPG 1.61 kg CO₂/L. Electric uses your grid factor (FR ~0.05, EU avg ~0.25, US avg ~0.39 kg/kWh). Tree offset: ~25 kg CO₂/yr per mature broadleaf.
Personal transportation is the largest individual source of CO₂ emissions for most adults in developed countries, ahead of housing energy and even diet. The numbers are big and easy to underestimate: 15 000 km/yr in a typical petrol car emits ~2.4 tonnes of CO₂ — about 25 % of an EU citizen's full carbon budget under a 1.5 °C trajectory. Yet most drivers have no quantitative sense of their own vehicle's footprint because the dashboard never shows it. This calculator connects the everyday inputs — fuel type, fuel consumption per 100 km, annual mileage — to a yearly CO₂ figure, with branches for electric vehicles (where the grid factor matters), and contextualizes it by computing per-km emissions, per-occupant share for carpooling, and an indicative tree-offset count.
Combustion-fuel branch (petrol, diesel, E85, LPG):
CO₂_per_km (kg) = (consumption_L_per_100km / 100) × CO₂_factor_per_L.
CO₂ factors (kg CO₂ / L of fuel) are tank-to-wheel, from ADEME 2024 base carbone: - Petrol: 2.31. - Diesel: 2.69 (more carbon-dense per litre). - E85 (85 % ethanol blend): 1.6. - LPG: 1.61.
Electric-vehicle branch: consumption is in kWh / 100 km (typical 14–20).
CO₂_per_km (kg) = (consumption_kWh_per_100km / 100) × grid_factor_kg_per_kWh.
Grid factors vary by country: France ~0.05 (mostly nuclear + hydro), EU average ~0.25, US average ~0.39, Poland ~0.65 (coal-dominant). The user enters their grid factor as a free input.
Yearly total: CO₂_year (kg) = CO₂_per_km × annual_km.
Per-occupant share: CO₂_year / occupants — the carpool factor. A 4-person commute is 4× greener per person than a solo commute.
Tree offset: CO₂_year / 25 — a mature broadleaf tree absorbs ~22–28 kg CO₂ per year over its lifetime; the calc rounds to 25 kg/yr/tree as the integer baseline.
Pick the fuel type (petrol, diesel, E85, LPG, electric). Enter the consumption per 100 km (L for combustion, kWh for electric). Enter the annual mileage. For electric, enter your local grid CO₂ intensity (kg CO₂ / kWh — defaults to 0.25 for EU average). Enter the average occupants per trip (≥ 1; carpool reduces per-person emissions). The calc returns yearly emissions in kg and tonnes, per-km in g, total fuel/energy consumption, equivalent trees needed for offset, and a 12-month visual breakdown.
Petrol commuter: 7 L/100 km, 15 000 km/yr, solo.
Diesel family car: 5.5 L/100 km, 20 000 km/yr, 4 occupants.
Electric on French grid: 17 kWh/100 km, 15 000 km/yr, grid 0.05 kg/kWh.
Tank-to-Wheel only. The calc uses TTW factors — direct combustion CO₂. Well-to-Wheel (WTW) adds upstream extraction, refining, transport: ~25 % more for fossil fuels, accounting for refining and crude transport. ADEME publishes both; this calc uses TTW for compatibility with vehicle nameplate emissions data.
Vehicle manufacturing footprint. A new car has 5–15 t CO₂ embedded in its production, dominated by the battery for EVs (40–80 kg CO₂ per kWh of battery capacity). Over a 200 000 km lifetime, that's 25–75 g CO₂/km extra. The calc shows operational emissions only — meaningful comparisons between EV and ICE need lifecycle math.
Real-world vs WLTP consumption. EU homologation gives WLTP figures that under-estimate real-world consumption by 10–20 % for ICE and 15–30 % for EVs in cold weather. Use your dashboard average, not the brochure figure.
Marginal vs average grid. The grid factor here is the average mix. Charging an EV at peak demand pulls from marginal (often gas-fired) plants in many grids — the marginal factor can be 50–100 % higher than average. For environmentally-optimized charging, time-of-use grid intensity matters.
E85 carbon accounting. The 1.6 kg/L factor reflects the ethanol-CO₂ being counted as biogenic (re-absorbed by plants). Strict critics include indirect land-use change and reach 2.0+. ADEME's 1.6 is the EU regulatory figure.
Hybrid vehicles. Plug-in hybrids (PHEV) split between fuel and electric — neither branch alone applies. Estimate as: (electric_km × electric_factor) + (fuel_km × fuel_factor). Real-world PHEV often runs more on fuel than the manufacturer claims.
LPG and CNG. LPG factor 1.61. CNG (natural gas) ~2.7 kg CO₂/m³. The calc has an LPG option but not CNG explicitly.
Tree offsetting is not a real solution. Counting "trees needed to offset" is rhetorically useful but misleading: forests take decades to grow, can be felled or burn, and most "tree offset" programs have suspect additionality. Real decarbonization is reduction, not offset.
Carpool double-counting. If two people each enter their solo emissions, summing gives double the actual emissions. The "occupants" field is the average; for full accounting attribute the trip's emissions per person.
Driving style. Aggressive driving + air-conditioning increase real consumption by 15–30 %. Eco-driving (anticipation, smooth acceleration, gentle deceleration) reduces by 5–15 %.