Weekly Food Carbon Calculator
Estimate the annual CO₂ your diet produces based on weekly meat, dairy, and vegetable servings and how much food you buy locally. Use it to see the impact of dietary shifts like Meatless Monday.
About this calculator
Food production is responsible for about 26% of global greenhouse gas emissions, and what you eat matters far more than how far it travelled. This calculator uses the formula: Annual CO₂ (kg) = ((meat × 2.5 + dairy × 0.9 + vegetables × 0.3) × (1 − local/100 × 0.2)) × 52. The per-serving emission factors (kg CO₂e) reflect life-cycle analysis averages: meat at 2.5 kg, dairy at 0.9 kg, and vegetables at 0.3 kg per serving. The local sourcing discount applies a 20% maximum reduction proportionally, since locally grown food avoids long transport emissions. Multiplying by 52 converts the weekly total to an annual figure. Note that 'meat' here blends beef, pork, and poultry averages — beef alone is considerably higher at ~6 kg CO₂e per serving.
How to use
Example: 7 meat servings, 5 dairy servings, 10 vegetable servings per week, with 50% locally sourced food. Step 1 — Weekly raw total: (7 × 2.5) + (5 × 0.9) + (10 × 0.3) = 17.5 + 4.5 + 3.0 = 25 kg CO₂e. Step 2 — Apply local discount: 25 × (1 − 0.50 × 0.2) = 25 × 0.90 = 22.5 kg CO₂e/week. Step 3 — Annualise: 22.5 × 52 = 1,170 kg CO₂e/year. Reducing meat servings from 7 to 3 per week would drop the annual figure by roughly 260 kg CO₂e.
Frequently asked questions
How much CO₂ does cutting meat from my diet actually save per year?
Each meat serving in this calculator carries an emission factor of 2.5 kg CO₂e, representing a blend of beef, pork, and poultry. Removing one meat serving per week saves roughly 130 kg CO₂e annually (2.5 × 52). If you replaced all 7 weekly meat servings with vegetables (0.3 kg CO₂e each), you'd save about (2.5 − 0.3) × 7 × 52 ≈ 800 kg CO₂e per year — nearly a tonne. Note that beef has a much higher impact than poultry, so swapping red meat for chicken is a significant partial step even before going fully plant-based.
Does buying local food really reduce my food carbon footprint significantly?
Transport typically accounts for only 5–10% of a food's total life-cycle emissions, so 'food miles' matter far less than the production method. This calculator reflects that by capping the local sourcing discount at 20%. A locally raised beef steak still emits far more CO₂ than an imported lentil, because cattle farming (methane from digestion, land use change) dominates beef's footprint. Local sourcing does offer other benefits — supporting regional farmers, freshness, and reduced refrigeration — but it should be seen as a secondary lever rather than the primary way to cut food emissions.
What are the emission factors for common foods and why do they vary so much?
Emission factors reflect the entire supply chain: land use, fertilisers, animal digestion, processing, and transport. Beef is among the highest at roughly 27 kg CO₂e per kg of product, largely due to methane from cattle and land cleared for grazing. Lamb is similarly high at ~24 kg CO₂e/kg. Pork and poultry are lower at 7–6 kg CO₂e/kg, dairy averages around 3 kg CO₂e/kg, and most vegetables fall between 0.4–2 kg CO₂e/kg. The serving-based factors in this calculator (2.5, 0.9, 0.3 kg) are weighted averages across typical consumption patterns, providing a useful approximation for personal footprint estimation without requiring per-food-item detail.