How We Calculate
Food Miles
Every producer on Sustainfind shows how far your food has travelled compared to the supermarket average. Here’s exactly how we work it out.
What we show you
Every producer profile displays two food miles figures — a direct comparison that makes the environmental case tangible.
Calculated in real time from the producer’s location to your postcode using the Haversine formula.
A weighted average showing how far that food category typically travels to reach a UK shelf.
See the comparison
These are real comparisons based on a Nottingham postcode and actual category benchmarks.
How we calculate the benchmark
Our supermarket averages are built from publicly available UK trade and agricultural data. For each food category, we follow four steps.
Establish UK self-sufficiency
What proportion of this food is produced domestically versus imported? For example, the UK is approximately 86% self-sufficient in beef, but only 16% self-sufficient in fresh fruit.
Identify import sources
Which countries supply UK imports, and what share does each contribute? For lamb, approximately 70% of imports come from New Zealand, with the remainder from Australia and Ireland.
Calculate source distances
We determine the approximate shipping or road distance from each source country to the UK, measured as the primary trade route distance.
Compute weighted average
The domestic share counts as approximately zero food miles. Each import source is weighted by its share of imports multiplied by its distance. The result is a single representative benchmark.
Lamb
Weighted average: ~3,200 miles. Here’s how that breaks down.
Our data sources
The honest picture
We believe in transparency. Food miles are a powerful indicator, but they’re not the complete story.
Production matters too
A UK tomato grown in a heated greenhouse in January may have a higher carbon footprint than one shipped from Spain where it grew in natural sunlight. We present food miles as a directional indicator, not a definitive environmental audit.
Transport mode varies
Food shipped by sea over long distances can have lower emissions per mile than food transported by road over shorter distances. Our benchmarks reflect distance, not the specific transport mode used.
Averages, not absolutes
Our supermarket benchmarks are weighted averages based on national trade data. Individual products may have travelled more or less than the average. We use the tilde (~) to signal approximation.
Some things can’t be local
Coffee, tea, chocolate, and citrus will always travel long distances. But where local alternatives exist — and they exist for far more products than most people realise — choosing them makes a real, measurable difference.
The 20-mile threshold
Sustainfind shows you producers within approximately 20 miles of your postcode. This isn’t arbitrary — it’s grounded in environmental logic.
Aligned with zero-emission delivery options like e-cargo bikes and walking collection.
Within Royal Mail’s consolidated local delivery network — the UK’s largest and greenest for last-mile parcels.
See it in action
Enter your postcode and discover how close your local producers really are.
Find Local Producers →