CO2 Emissions Calculator

Estimate journey and annual emissions with clear assumptions.

Add a distance, fuel type, and efficiency to estimate CO2 for a single journey. If you have annual mileage, include it to see a yearly estimate.

Want to refine efficiency first? Try the fuel efficiency calculator before you run this check. For regional context, browse the locations hub .

When to use this calculator

Use this when you need a simple emissions estimate for a trip, commute, or reporting discussion.

Inputs

UK units

Enter the distance you want to measure, and add annual mileage if you want a yearly estimate too.

Distance (miles)Annual mileage (optional)

Choose the fuel and unit, then enter your MPG or litres per 100 km.

Fuel typeEfficiency unit

MPG

Prefilled with 35 MPG (admin-configured).

Emissions contextUK factors

We show sources and dates for the emissions factors used.

Enter journey distance in miles.

Fill in the form to see your results.

How this is calculatedv

You enter distance, efficiency, and fuel type.
We estimate litres consumed for that journey.
We apply configured CO2-per-litre factors to estimate trip and annual emissions.