Diet Carbon Footprint Calculator

Each food item is assigned a carbon intensity value measured in kg CO₂ equivalent (CO₂e) per serving. This accounts for greenhouse gases released across the full supply chain — from land use and animal digestion to processing, packaging, and transport. The figures used in this calculator are based on global averages from peer-reviewed research.

Greenhouse gases (GHGs) include carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Food production releases all three: CO₂ from land clearing and machinery, methane from livestock digestion, and nitrous oxide from fertilized soils. These are combined into a single CO₂-equivalent (CO₂e) metric for comparison.

Beef has the highest carbon footprint of any common food — roughly 27 kg CO₂e per kg of beef — due to the methane cattle emit, the vast land area required for grazing, and the feed crops needed to raise them. Compared to chicken or legumes, beef can produce 10–20x more emissions per gram of protein.

Research published in Nature Food estimates that vegan diets produce roughly 50–70% fewer dietary greenhouse gas emissions than high-meat omnivore diets. The biggest gains come from eliminating beef, lamb, and dairy. Even reducing meat intake to a few times per week can meaningfully cut your food-related carbon footprint.

CO₂e stands for 'CO₂ equivalent' — a standardized unit that converts different greenhouse gases into a single number based on their global warming potential over 100 years. Your annual figure sums up the climate impact of all your weekly food choices multiplied across 52 weeks.

The calculator converts your annual food emissions into an equivalent number of kilometers driven in an average petrol car, which emits approximately 0.21 kg CO₂e per km. This comparison makes the abstract number more tangible — for example, 2,000 kg CO₂e is roughly equivalent to driving about 9,500 km.

This calculator uses standard serving sizes common in nutrition research: 3 oz (85g) for meat, 3.5 oz (100g) for fish, 1 egg for eggs, 1 cup (240ml) for milk/yogurt, 2 oz (55g) for cheese, 0.5 cup cooked for beans and rice, and 1 cup or ~140g for fruits and vegetables. When in doubt, round to the nearest whole serving.

Absolutely. Run the calculator now to get your baseline, then experiment with reducing high-emission foods like beef, cheese, and pork. Even swapping one beef meal per week for chicken or beans can save hundreds of kilograms of CO₂e annually. Recalculate after dietary changes to measure your impact.