Tools for carefully estimating carbon footprints have tended to be difficult to use and clunky in appearance. Two recently introduced calculators make real improvements and allow individuals and companies to carry out effective analysis of carbon emissions.

10:10 footprinter 10:10 footprinter is a free tool from Best Foot Forward, the UK's leading analysts of corporate footprints. Register here. It offers a calculator with attractive graphics and easy data entry. One of the targets is the list of 2,000 or so businesses that have signed up for the 10:10 campaign. Membership of 10:10 commits a company to reduce its emissions by 10% during 2010 and the footprinter allows its managers to check progress against the target.

10:10 footprinter allows companies to input data from invididual offices, subsidiary companies, and divisions. Inputs can include electricity use, gas, cars, and aviation. Data can be amalgamated and results can be compared between separate parts of the company and for different periods of a calendar year. Best Foot Forward will provide and update all the input data, such as the right figure to use for the carbon emissions from a kilowatt hour of electricity.

The thing I most liked about the calculator was its very effective and colourful graphics. It's easy to use, even for a small company. For businesses that need to show their emissions performance for supplier audits and other purposes, this is an extremely useful tool. One small criticism: I would have liked to have been able to enter different CO2 figures for different types of cars.

iMeasure Oxford's Environmental Change Unit has put together a website allowing individual householders to enter their gas, electricity and water consumption each week. Register here.

The calculator estimates the resulting CO2 emissions for each member of the household and compares it to similar properties for the week in question. At the time I entered my data early in January the website had 500 or so members so the comparative information is already quite good. Over time, this website will develop extremely useful data about patterns of energy use for different types of household. I suggest that the ECI should ask us for a lot more demographic information so that they can get a better feel for what drives household energy consumption.

Very easy to use. Interesting results, and the information from other households will prove an interesting competitive spur. Last week our house was a bit better than average but having five people holed up in the snow all week may have increased our figures this week to above the mean. A must for carbon cutting clubs - individuals can chart their performance against other members.