Zero Waste Calculator - Diversion Rate

Waste diversion rate is the percentage of solid waste that is diverted away from landfill through recycling, composting, or reuse:

Diversion rate = (recycled + composted + reused) / total waste x 100%

The zero waste movement targets a 90% diversion rate. San Francisco, which has one of the best municipal programs in the US, achieves around 80%. Most US cities average 32-35%.

Landfilling organic waste is particularly wasteful: food and yard waste decomposes anaerobically in landfills, producing methane (a potent greenhouse gas). Composting the same material produces carbon dioxide and soil amendments instead, cutting the climate impact by roughly 80%.

Approximate CO2 savings by diversion method (kg CO2e saved per kg of waste):

• Recycling aluminum: 9.5 kg (vs. virgin smelting)
• Recycling cardboard/paper: 0.7 kg
• Recycling plastic: 1.5 kg
• Composting food waste: 0.5 kg (vs. landfill methane)
• Recycling glass: 0.3 kg

The economics also favor diversion: landfill tipping fees in the US range from $30-150 per tonne, while recycling processors pay for clean streams of aluminum, cardboard, and metals. The main challenge is contamination, and a single greasy pizza box can ruin a load of paper recycling.

Most municipal programs accept: cardboard, paper, metals, glass, and plastics 1 and 2. Soft plastics (bags, wrap), food-contaminated items, and styrofoam typically go to landfill unless specialized programs exist.

One honest caveat about the CO2 figure

Look at that list of factors again and note the spread: aluminum saves 9.5 kg per kg recycled, glass saves 0.3. That is a factor of thirty, and a household bin is a mixture, so no single number can be right for everyone. This calculator applies about 0.9 kg per kg to the recycling stream, which is a reasonable weighted average for a typical kerbside mix of paper, cardboard, glass and a little metal and plastic. If your recycling is unusually aluminum-heavy the real saving is several times higher. If it is mostly glass bottles it is lower.

The diversion rate itself has no such uncertainty, which is the argument for treating it as the headline number and the CO2 as a rough companion.

A rate is not the whole story

Two households can both hit 70% diversion while one produces 5 kg of waste a week and the other 20. The rate rewards sorting, not reducing, and the second household is doing three times the damage with an identical score. Watch the landfill kilograms alongside the percentage. The genuinely zero-waste move is the packaging that never enters the house, and nothing in a diversion rate can see it.