Using government-recognised data and calculations, people can calculate their carbon footprint using the tool, developed by the Department for Environment, Food And Rural Affairs as part of its Act On C02 campaign.

Calculations are taken from home energy use, appliances and transport, and you can choose to calculate either your own personal footprint or your household's.

The calculator then develops a personalised action plan for users and suggested changes.

Research commissioned by Defra has shown that 94% of people in Britain now believe that the world's climate is changing and 66% of people surveyed said they were already trying to take personal action to limit climate change.

The underlying software that runs the calculator's 'engine' will be made freely available under 'open source' licences, to enable others wanting to power their own calculators to use it. The software developers d::gen network limited will be licensing the underlying software and algorithms under "open licenses" such as the GNU General Public License, Creative Commons or equivalents.

The calculator is a public 'trial' or beta version, and there are plans to develop and improve it using feedback and ideas from users. Feedback on the calculator can be emailed to calculator.feedback@defra.gsi.gov.uk.

Information on the methodology for the calculator including data, factors and assumptions can be found here.