Scan a Barcode, See the Carbon

Two scanners, two situations

The barcode scanner — for packaged food

Point the camera at a product barcode and Decarbonr pulls its record from OpenFoodFacts, the largest open food database in the world, covering 2.9 million-plus products. You get a CO₂e estimate for the item in front of you, plus lower-carbon alternatives in the same category. This is the tool for the aisle, the pantry, and the weekly shop — anywhere the food still has packaging on it.

The AI meal scanner — for everything else

Restaurant plates and home cooking have no barcode. For those, photograph the meal and the AI scanner (GPT-4 Vision) identifies what is on the plate and estimates its footprint ingredient by ingredient, with suggestions for lower-carbon swaps. It is the difference between logging “lunch” and knowing that the beef in it did most of the work.

A single swap inside one dish moves the number by an order of magnitude. That range is only visible if the estimate is broken down — a whole-meal total hides exactly the information you would act on.

Where scanning fits in the rest of the picture

Food is one input. Decarbonr also logs journeys across 9 transport modes using per-kilometre factors from the European Environment Agency and the IPCC, and tracks 12+ lifestyle categories — heating, electricity, water, waste, digital and more — each colour-coded by impact. All of it rolls into one daily number, comparable against national averages worldwide and against the 2-tonne annual target aligned with 1.5°C.

That is the point of scanning rather than estimating: once food is measured instead of guessed, you can see honestly whether it is your largest category or not. For many people it is not, and the effort belongs elsewhere.

What a week of scanning actually tells you

A single scan is a data point. A week of them is a shape. Most people who start logging discover that their food footprint is dominated by a small number of repeated items rather than by occasional indulgences — the everyday sandwich, not the birthday dinner. That is difficult to notice by memory and obvious in a log.

Decarbonr turns that record into the parts of the app that make it useful: a visual dashboard, country-specific reduction tips, comparisons against national averages, and goals, streaks, and achievements to keep the habit going. There is also a built-in library of timelines, explainers, calculators, country data, and quizzes for the context behind the numbers. Scanning is just the fastest way to get honest data in.