Daily Commute Carbon Calculator
Estimate the annual CO₂ your commute produces based on distance, transport mode, and working days. Use it to compare switching from driving to cycling or public transit.
About this calculator
Every mode of transport emits a different amount of CO₂ per kilometre travelled. The calculator multiplies your round-trip distance (km) by an emission factor for your chosen transport mode (kg CO₂/km), then scales that by your annual working days: Annual CO₂ (kg) = distance × transport_factor × workdays / 1000. The division by 1000 converts grams to kilograms. Emission factors vary widely — a petrol car emits roughly 170 g CO₂/km, a bus around 89 g/km, and cycling or walking effectively zero. By comparing modes, you can see exactly how much carbon you'd save by switching, which is useful for personal climate goals or corporate sustainability reporting.
How to use
Suppose you drive 30 km round-trip, 230 working days per year, and your car's emission factor is 170 g CO₂/km. Step 1 — Enter distance: 30 km. Step 2 — Select transport mode (petrol car, factor = 170). Step 3 — Enter 230 working days. Calculation: 30 × 170 × 230 / 1000 = 1,173 kg CO₂ per year. That is roughly 1.17 tonnes of CO₂ annually just from commuting — equivalent to about 4,600 km of long-haul flying.
Frequently asked questions
How does transportation mode affect my commute carbon footprint?
Each transport mode burns different fuels (or none at all) and carries different numbers of passengers, so the per-kilometre CO₂ figure varies enormously. A solo petrol car emits roughly 170 g CO₂/km, a diesel bus around 89 g/km per passenger, a train about 41 g/km, and cycling or walking produces near-zero operational emissions. Switching from a car to public transit for a 30 km daily round-trip can save over 600 kg of CO₂ per year. These figures are averages; actual emissions depend on vehicle age, load factor, and local energy mix.
What counts as a reasonable number of working days per year for this calculator?
A standard full-time worker in most countries works approximately 230–260 days per year after subtracting weekends, public holidays, and typical annual leave. In the UK the figure is commonly cited as 232 days; in the US it is around 250. If you work part-time, work from home some days, or commute irregularly, adjust accordingly — even removing two remote-working days per week drops your commuting days to about 130, which can cut your annual commute emissions nearly in half.
Why is my annual commute carbon footprint higher than I expected?
Daily distances and emission factors seem small in isolation, but they compound dramatically when multiplied by 230+ working days. A 20 km round-trip by petrol car at 170 g/km clocks up about 782 kg CO₂ per year — close to three return economy flights from London to Amsterdam. Many people underestimate their footprint because they only think about individual trips rather than the annual total. The calculator makes that full-year impact visible so you can set meaningful reduction targets.