Composting impact and plastic footprint are two household waste-scenario worksheets, and both are honest about what they are not. The composting impact calculator multiplies waste mass by factors you enter to estimate avoided emissions and compost yield. The plastic footprint calculator annualizes a measured item frequency and mass into kilograms per year — and says plainly that the result is a mass scenario, not a lifecycle impact. Together they cover the two ends of household waste: the organics you can divert and the plastic you consume.
What each calculator does
The composting impact calculator takes a food-waste mass and multiplies it by two factors you enter: an avoided-emissions factor in kilograms of CO2e per kilogram, and a compost-yield factor in kilograms per kilogram. For 100 kg of food waste with factors of 0.20 kg CO2e/kg and 0.50 kg/kg, it returns 20.0 kg CO2e avoided and 50.0 kg of compost. The calculator supplies no factors itself — all emissions and yield values are entered by you — and it labels the low and high endpoint range as sensitivity, not a confidence interval.
The plastic footprint calculator takes items per week, a measured grams-per-item mass, and the number of weeks represented, then computes annual mass as items/week × g/item × weeks ÷ 1,000. Its worked example: 20 items per week at 12 g each over 52 weeks gives 12.48 kg/year; reducing frequency to 15 items per week gives 9.36 kg/year. No default item weight, material composition, or regional benchmark is supplied — you define exactly what counts as one item and record how its mass was measured.
Side-by-side
| Composting impact calculator | Plastic footprint calculator | |
|---|---|---|
| Question it answers | What does diverting this organic waste save? | How much plastic mass do I use in a year? |
| Key inputs | Waste mass, entered avoided-emissions factor, entered yield factor | Items per week, measured grams per item, weeks |
| Primary outputs | kg CO₂e avoided and kg of compost | Annual plastic mass in kg/year |
| Formula | Waste mass × entered factors | Items/week × g/item × weeks ÷ 1,000 |
| Factors supplied | None — all entered by you | None — item definition and mass measured by you |
| Result framing | Scenario with sensitivity range, not confidence interval | Mass scenario, not lifecycle environmental impact |
| Typical use | Comparing waste-diversion scenarios for food scraps and yard waste | Establishing a plastic-use baseline and testing frequency changes |
When to use which
Use the composting impact calculator when your question is about diverting organic waste: how much CO2e a food-scrap or yard-waste stream might avoid, and how much compost it could yield. Because the factors are yours, record their method, geography, year, and boundary alongside the result, and re-run the low and high endpoints as sensitivity cases.
Use the plastic footprint calculator when you want an annual plastic-mass baseline from your own observation. Measure a representative sample, count the same item definition for several weeks, then annualize. The page’s built-in scenario pattern — change frequency while holding item mass fixed — isolates one variable at a time, which the composting impact worksheet mirrors when it varies one factor endpoint at a time.
The two pages are designed as siblings: the plastic footprint article points to the composting impact calculator as another household waste-scenario tool, and both keep the same discipline of visible assumptions, no supplied empirical factors, and explicit boundaries.
Limits and disclaimer
Both pages are scenario worksheets, not inventories, certifications, offsets, or compliance filings. The composting impact result excludes landfill, water, tree, or universal-benefit equivalents and depends entirely on the factors you enter; the plastic footprint result excludes uncounted plastics, secondary packaging, manufacturing, recycling, disposal, leakage, toxicity, and emissions, so it should not be compared with regional per-capita statistics unless definitions, years, and system boundaries are aligned. Neither result should be treated as a confidence interval, and both are educational estimates for comparing directional scenarios.