About the Food Carbon Footprint Calculator
This food carbon footprint calculator estimates the greenhouse gas emissions behind the food you eat. Enter roughly how much of each food you eat in a typical week and it multiplies each amount by its life-cycle emission factor, then totals the result per week and per year in kilograms and tonnes of CO₂-equivalent (CO₂e), which counts methane and nitrous oxide as well as carbon dioxide.
It is useful for anyone curious about how much their diet contributes to climate change, comparing meat-heavy, vegetarian and vegan eating, or testing a specific swap such as replacing beef with chicken or beans. The breakdown shows which foods dominate your footprint, which is usually one or two items rather than the whole plate.
Emission factors are the global averages per kilogram of food from the largest meta-analysis of food systems to date, Poore and Nemecek (2018, Science), covering about 38,700 farms in 119 countries and every stage from land-use change to retail, as published by Our World in Data (2010 reference year). Real products vary widely around these means by farm and country, and the factors cover the food as sold, not cooking or waste at home. Enter amounts for one person or a whole household; milk is entered in litres.
With the default inputs, the yearly food emissions is 3.7 t CO₂e. Change any value above to recalculate instantly.
How to use the food carbon footprint calculator
- 1Think about a typical week and estimate how much of each food you eat in kilograms (100 g = 0.1 kg).
- 2Enter milk in litres and coffee as the weight of beans or grounds used.
- 3Choose whether your beef mostly comes from beef herds or dairy herds.
- 4Read your weekly and yearly footprint and the largest source.
- 5Lower the amount of your top food, or try a vegetarian week, to compare.
Formula and method
Each food’s weekly quantity in kilograms (litres for milk) is multiplied by its emission factor in kg CO₂e per kg of product, and the results are summed. Factors are global mean values from Poore and Nemecek (2018) and include land-use change, farming, animal feed, processing, transport, retail and packaging, with methane and nitrous oxide converted to CO₂-equivalents over 100 years.
Beef from dedicated beef herds (99.48 kg CO₂e/kg) has far higher emissions than beef from dairy herds (33.3), because dairy cattle’s emissions are mostly allocated to milk. The beef-swap figure replaces your beef with the same weight of poultry at 9.87 kg CO₂e/kg. Cooking energy, food waste at home and shopping trips are not included.
- quantity_i
- Amount of food i eaten per week (kg, or litres for milk)
- factor_i
- Life-cycle emissions of food i in kg CO₂e per kg
Worked examples
Typical mixed diet
Just 300 g of beef a week produces 0.3 × 99.48 ≈ 29.8 kg CO₂e — over 40% of the 71.2 kg weekly total. Adding up all 16 foods gives about 3,704 kg (3.7 tonnes) a year, with animal products making up 86%. Replacing the beef with chicken would save about 1,398 kg a year.
Vegetarian week
Removing all meat and fish and adding more beans and tofu drops the weekly total to about 25.2 kg CO₂e, or 1.31 tonnes a year — about a third of the mixed diet. Dairy and eggs now account for 54% of the total, with 2 litres of milk the single biggest item.
Vegan week
A plant-only week with extra beans and tofu comes to about 12 kg CO₂e, or 623 kg a year. Coffee is now the largest item: 100 g of beans at 28.53 kg CO₂e per kg is 2.85 kg a week, more than all the vegetables combined.
More beef, but from dairy herds
Doubling beef to 600 g a week but sourcing it from dairy herds (33.3 kg CO₂e per kg) gives 20 kg CO₂e from beef and 61.4 kg in total, still below the default diet with beef-herd beef. Swapping it for chicken would save about 731 kg a year.
Frequently asked questions
Which foods have the highest carbon footprint?+
Per kilogram, beef from dedicated beef herds is highest at about 99 kg CO₂e, followed by dark chocolate (about 47), lamb (40), farmed prawns (27), coffee (29 per kg of beans) and cheese (24). Most plant foods such as grains, vegetables, fruit, beans and nuts are below about 2 kg CO₂e per kg.
Does eating local food cut emissions a lot?+
Usually less than people expect. In the Poore and Nemecek data, transport is typically a small share of a food’s total footprint (often under 10%), while land use and farm-stage emissions such as cattle methane dominate. What you eat matters far more than where it comes from, except for air-freighted produce.
How much CO₂ does a vegetarian or vegan diet save?+
It depends on what is replaced, but cutting meat typically removes the largest part of a diet’s footprint. In the examples here, going vegetarian cuts food emissions by about two thirds and going vegan by over 80%, mainly by removing beef and other ruminant meat.
What does CO₂e mean?+
CO₂-equivalent combines all greenhouse gases into one number by weighting each by its global warming potential over 100 years. Food emissions include a lot of methane from cattle and rice paddies and nitrous oxide from fertiliser, which are converted to the amount of CO₂ with the same warming effect.
Why is beef so much higher than chicken?+
Cattle convert feed to meat inefficiently, need large areas of pasture and cropland, and their digestion releases methane, a potent greenhouse gas. Chickens grow quickly on much less feed and produce no enteric methane, so a kilogram of poultry has about a tenth of the emissions of beef from a beef herd.