Food Miles Calculator
Calculate food miles with our free science calculator. Uses standard scientific formulas with unit conversions and explanations.
Formula
CO2 = (Weight in tons) x (Distance in km) x Emission Factor
Total CO2 equals food weight in metric tons times distance in km times the transport mode emission factor in kg CO2 per ton-km. Factors: air 0.602, truck 0.062, rail 0.022, ship 0.008, van 0.150. Refrigeration adds 20 percent. Local comparison uses 50 km truck baseline.
Worked Examples
Example 1: Cross-Country Produce Shipment
Problem: 1,000 kg of refrigerated produce by truck 2,500 km from California to New York.
Solution: Ton-km = 1 x 2500 = 2,500 Factor = 0.062 x 1.20 = 0.0744 CO2 = 2500 x 0.0744 = 186.00 kg Per kg = 186 g Local (50 km) = 3.72 kg Savings = 98.0%
Result: CO2 = 186.00 kg | Per kg = 186 g | Local saves 98.0%
Example 2: Air vs Ocean Shipping
Problem: 500 kg berries air-freighted 8,000 km vs 500 kg apples shipped 12,000 km by ocean. Both refrigerated.
Solution: Air: 0.5 x 8000 x 0.602 x 1.2 = 2,887.60 kg CO2 Ocean: 0.5 x 12000 x 0.008 x 1.2 = 57.60 kg CO2 Air emits 50x more despite shorter distance
Result: Air = 2,888 kg | Ocean = 58 kg | 50x difference
Frequently Asked Questions
What are food miles?
Food miles refer to the distance food travels from where it is produced to where it is consumed by the end customer. The concept was introduced by Tim Lang in the early 1990s as a measure of environmental impact of food transportation. Food miles are usually expressed in kilometers or miles and can be calculated for individual items or an entire diet. The average American meal has traveled approximately 2,400 km from farm to plate. While food miles provide a simple intuitive metric, they are an incomplete measure because they do not account for the efficiency of different transport modes or production-stage emissions.
How are food transportation emissions calculated?
Food transportation emissions are calculated by multiplying the weight of food by the distance traveled and by the emission factor for the transport mode, expressed in kg CO2 per ton-kilometer. Different transport modes have vastly different emission factors: air freight produces about 0.6 kg CO2 per ton-km, road trucks about 0.06 kg, rail about 0.02 kg, and ocean shipping about 0.008 kg. Refrigeration typically adds 15 to 25 percent to transport emissions. Multi-modal journeys require calculating each segment separately and summing the results for total emissions.
How does refrigeration affect food transport emissions?
Refrigerated transport adds approximately 15 to 25 percent to the energy consumption and emissions of food transportation. Refrigeration units on trucks consume diesel continuously, adding about 2 to 3 liters per hour. For ocean containers, reefer units account for about 20 percent of a ship total electricity consumption. The impact varies by journey duration. Despite the energy penalty, cold chain infrastructure is essential for reducing food waste, which generates far more emissions than the refrigeration energy when food spoils and decomposes anaerobically.
What percentage of food emissions come from transportation?
Transportation accounts for approximately 5 to 10 percent of total greenhouse gas emissions of the food system globally, though this varies significantly by product. For plant-based foods shipped by sea or land, transport may represent less than 5 percent of lifecycle emissions. For air-freighted products, transport can account for 50 to 90 percent. The dominant emission sources in the food system are land use change, on-farm activities like fertilizer use and livestock methane, and food waste, which collectively account for about 80 percent. This is why dietary choices generally have a larger climate impact than minimizing food miles.
How do food miles vary by product type?
Food miles vary enormously by product. Staple grains like wheat, rice, and corn are often grown domestically, traveling hundreds to a few thousand kilometers by ship or rail. Fresh fruits and vegetables may travel 2,000 to 10,000 km, with some products being air-freighted from the Southern Hemisphere. Seafood can travel extreme distances, with shrimp from Thailand or salmon from Norway reaching global markets. Processed foods often have complex supply chains where ingredients from multiple countries are assembled at centralized factories. Coffee, cocoa, and tropical spices routinely travel 8,000 to 15,000 km but do so efficiently by ocean container.
What is the last mile problem in food delivery?
The last mile refers to the final leg of food delivery from a retail store or distribution center to the consumer home. Despite being the shortest segment, it is often the most emission-intensive per kilometer because it involves small vehicles making multiple stops with partially loaded cargo. Home delivery by van produces approximately 0.15 kg CO2 per ton-km, more than double the rate for large trucks. However, well-optimized delivery routes with high drop density can actually produce lower emissions per household than individual car trips to the supermarket. The environmental impact depends heavily on delivery consolidation.