The online "tailor-made carbon footprint calculator" allows fresh-produce companies to work out their emissions and pinpoint where to make improvements.
"By understanding where carbon emissions are found within the industry, the sector can target environmentally-friendly initiatives," said chief executive Nigel Jenney.
"We can find out where they are needed most and can counter any exaggeration of the environmental impact of the production and distribution of fruit and vegetables.
"Having online access to an effective carbon footprint calculator is a key way the fresh-produce industry can help promote itself and reject misleading arguments."
The FPC worked with consultant Brown & Co on the calculator.
Environmental consultant Tony Hargreaves said measuring the carbon footprint of a cauliflower, a kilo of raspberries or a bunch of leeks was complex. It involved energy inputs in the processing, storing and packaging stages of the chain, as well as waste produced.
Covent Garden Market Authority's 260 tenants piloted the tool, said chief executive officer Jan Lloyd.
"We now have a baseline on which to target and measure our reduction achievements. Every organisation should assess emissions and look to reduce their carbon footprint."