Composting CO2 Savings Calculator
Calculate how much CO2 and methane you prevent by composting your food and garden waste instead of sending it to landfill.
Why composting matters for the climate
When organic waste (food scraps, garden clippings, paper) is sent to landfill, it breaks down anaerobically — without oxygen. This process produces methane (CH₄), a greenhouse gas approximately 84 times more potent than CO₂ over a 20-year period. Globally, landfill is one of the largest human-made sources of methane emissions.
Composting vs landfill
Composting is an aerobic process. Organic material breaks down in the presence of oxygen, primarily releasing CO₂ and water — not methane. The net climate benefit comes from:
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Avoided methane: Composting prevents the bulk of the methane that would have been produced in landfill. Estimates suggest 1 kg of food waste in landfill generates approximately 0.5–1.2 kg of CO₂ equivalent (mostly methane) over time. This calculator uses a conservative figure of 0.7 kg CO₂e per kg food waste.
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Carbon sequestration: Finished compost applied to soil locks carbon in the ground, improving soil health while sequestering additional CO₂. This adds approximately 0.15 kg CO₂e saved per kg of compost produced.
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Reduced transport emissions: Less waste going to landfill means fewer collection truck journeys, saving an estimated 0.05 kg CO₂e per kg of waste.
Total saving: approximately 0.9 kg of CO₂ equivalent per kilogram of organic waste composted rather than landfilled.
The composter’s impact
The average household generates 4–8 kg of compostable waste per week. A family composting 5 kg per week saves roughly 234 kg of CO₂e per year — equivalent to driving approximately 1,200 km in an average petrol car.