See the CO₂e you avoid each year by composting food and yard waste instead of landfilling it, using EPA WARM landfill-methane factors.
General kitchen food waste — vegetables, fruit, grains and small amounts of dairy.
A simple open, hand-turned pile at home — no transport emissions.
The share of methane a landfill collects instead of releasing. The WARM national-average landfill captures about 68%; landfills without gas collection capture 0%, so composting avoids even more there.
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Composting food and yard waste keeps it out of the landfill, and out of the atmosphere. Buried in a landfill, organic waste rots without oxygen and releases methane — a greenhouse gas about 28 times more potent than CO₂. This calculator uses EPA Waste Reduction Model (WARM) factors to show exactly how much CO₂-equivalent you avoid each year by composting instead, counting both the avoided landfill methane and the carbon stored when finished compost is returned to the soil.
When food and yard waste decompose without oxygen in a landfill, they generate methane. Wasted food alone is responsible for a large share of landfill methane emissions. Composting breaks the same material down aerobically — with oxygen — producing far less methane, and the finished compost stores carbon in soil while replacing synthetic fertiliser. The saving is the landfill emissions you avoid minus the small emissions of composting itself.
Emissions Reduction Formula
Households starting or expanding backyard composting to cut their footprint.
Urban residents using worm bins or community drop-off programs.
Shared sites quantifying the collective climate benefit of composting.
Food businesses measuring the emissions their composting program avoids.
Cities weighing the climate case for curbside organics collection.
Organisations documenting waste diversion and avoided emissions for ESG.
See exactly how many kilograms of CO₂-equivalent you keep out of the air each year by composting.
Composting mainly works by avoiding landfill methane — the dominant emission from rotting organics.
Applying finished compost to soil stores carbon and offsets fertiliser, adding to the benefit.
Modern landfills capture methane; older ones don't. Adjust the capture rate to see how it changes the saving.
Factors come from the EPA Waste Reduction Model, the standard reference for US waste emissions.
Composting food waste instead of landfilling it avoids roughly 0.7 metric tons of CO₂-equivalent per short ton (about 0.77 kg per kg) at an average landfill, per EPA WARM. A household composting 3 kg of food scraps a week avoids on the order of 100–150 kg CO₂e a year. Yard waste saves less per ton because it produces less methane; the exact figure depends on your landfill's gas-capture rate and whether you use the compost on soil.
It's the share of methane a landfill collects and flares or burns for energy instead of venting to the atmosphere. The EPA WARM national average is about 68%. Landfills with no collection capture 0% — so composting avoids much more methane there — while modern sites reach 80–90%. Even at high capture, composting still wins through soil carbon storage.
Yes, but far less than landfilling. Composting releases small amounts of methane and nitrous oxide, plus a little from turning and transporting the material. This calculator subtracts those process emissions from the benefit. Well-managed, aerobic composting keeps them low, and backyard methods avoid transport entirely.
This calculator isolates one action — composting food or yard waste instead of landfilling it — and quantifies just that saving in detail, including your landfill's gas-capture rate and soil carbon storage. The Household Waste Emissions Calculator gives your whole-bin footprint across paper, plastic, metal, glass and organics and every disposal route. Use this to plan composting and that one for the big picture.
When finished compost is applied to soil, part of its carbon is stored there for years, and it replaces energy-intensive synthetic fertiliser. In EPA WARM this soil-carbon credit is the largest part of composting's benefit. If you answer 'no' to using it on soil, the calculator drops that credit and shows only the avoided landfill methane.
High-moisture, high-volatile-solids foods — fruit and vegetables, dairy and cooked foods — generate the most methane as they break down fast. Drier items like bread and coffee grounds produce somewhat less. The calculator scales the landfill methane by waste type to reflect this, but all of them benefit from composting over landfilling.