Green Transportation Calculator

Compare the carbon emissions of different transport modes for any trip. Enter your trip distance, select a transport mode (car, bus, train, bike, walk, or EV), and optionally adjust passengers or fuel type. You'll see CO₂ emissions in grams, a comparison across all modes, and a breakdown showing how much you save versus driving alone.

km

Enter the one-way trip distance in kilometres.

Select how you currently travel.

Number of people sharing the car or EV (applies to car/EV only).

How many one-way trips do you make per year? (260 = 5 days/week)

Results

Your Trip Emissions

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Annual Emissions (Your Mode)

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CO₂ Saved vs. Solo Car (per trip)

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Annual CO₂ Saving vs. Solo Car

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Trees Needed to Offset Annual Emissions

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CO₂ Emissions by Transport Mode (g per trip)

Results Table

Frequently Asked Questions

How does the Green Transportation Calculator work?

Enter your trip distance, choose your transport mode, and specify how many passengers share the vehicle. The calculator applies standard emissions factors (grams of CO₂ per passenger-kilometre) for each mode to estimate your carbon output. It also scales results to an annual figure based on your trips-per-year input.

What emission factors are used for each transport mode?

The calculator uses widely accepted average figures: petrol car ~170 g CO₂/km, diesel car ~155 g/km, hybrid ~105 g/km, electric vehicle ~60 g/km (grid average), bus ~89 g/km per passenger, train ~41 g/km per passenger, bicycle and walking produce near-zero operational emissions. These figures are based on sources including the UK Department for Energy Security and Net Zero (DESNZ) and EPA greenhouse gas data.

Why are electric vehicles still shown with some CO₂ emissions?

EVs produce zero tailpipe emissions, but electricity generation itself has a carbon footprint that varies by country and energy mix. The calculator uses a global grid average. In regions with high renewable energy penetration, real-world EV emissions can be significantly lower.

What is carbon offsetting and how does it relate to my result?

Carbon offsetting means compensating for your emissions by funding projects that reduce or capture an equivalent amount of CO₂ elsewhere — such as reforestation or renewable energy projects. The 'trees needed' output gives you a rough sense of natural carbon sequestration required to offset your annual travel emissions (based on ~21 kg CO₂ absorbed per tree per year).

How do I reduce my transport carbon footprint?

Switching from a solo petrol car to public transport, carpooling, cycling, or an EV can cut per-trip emissions by 50–95%. Combining modes — for example, cycling to a train station — multiplies the benefit. Even increasing car occupancy from 1 to 2 passengers halves the per-person emissions.

Does the calculator account for trip frequency and annual impact?

Yes. Enter the number of one-way trips you make per year and the calculator will show your total annual CO₂ output for your chosen mode, plus the annual saving compared to driving alone in a petrol car. This helps visualise the long-term climate impact of modal choices.

Why is walking or cycling shown as zero emissions?

Cycling and walking produce no direct (operational) CO₂ emissions during the journey itself. While manufacturing a bicycle has some embodied carbon, it is extremely small per kilometre over the bike's lifetime and is not included here. For practical purposes these modes are treated as zero-emission travel.

Can I use miles instead of kilometres?

Yes. Select 'Miles (mi)' under Distance Unit and the calculator will automatically convert your input to kilometres before applying emissions factors, ensuring all results remain accurate regardless of which unit system you prefer.

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