Compost Bin Size Calculator
Calculate compost bin size from weekly food scraps and yard waste.
Returns cubic feet needed for hot composting, cold composting, or vermicomposting.
Compost bin size is determined by how much organic waste you generate and the minimum volume needed for a pile to heat up, which kills weed seeds and pathogens and accelerates decomposition.
The Minimum Volume Rule:
A compost pile must be at least 1 cubic meter (1 m³) to generate enough internal heat (55–65 °C) to compost efficiently.
Smaller piles still compost but take longer (6–18 months) and don’t heat up enough to kill pathogens.
Sizing Formula Based on Waste Generation:
Weekly waste (liters) × Turn cycle (weeks) × 2 = Required bin volume (liters)
The factor of 2 accounts for the fact that you need the current pile plus space to be building the next one.
Household Waste Reference:
| Household Size | Weekly Organic Waste |
|---|---|
| 1–2 people | 5–10 liters |
| 3–4 people | 10–20 liters |
| 5–6 people | 20–35 liters |
| Large garden (extra plant material) | +20–50 liters/week |
Worked Example:
Family of 4 generating 15 liters/week of kitchen + garden waste. Target turn cycle: 8 weeks.
Required volume = 15 × 8 × 2 = 240 liters per bin
Minimum hot-composting: 1,000 liters. → Use a 1,000-liter bin or two 500-liter bins in rotation.
Standard Bin Sizes:
| Bin Type | Volume | Best For |
|---|---|---|
| Small plastic tumbler | 100–280 L | 1–2 person household, no hot composting |
| Standard open bin | 300–600 L | Small families |
| Twin-bay system | 2 × 500–800 L | Active hot composting |
| Windrow / large pile | 1,000+ L | Serious gardeners |
Practical Tips:
- The ideal Carbon:Nitrogen ratio is 25–30:1 — alternate brown (straw, cardboard) and green (food scraps, grass) layers
- Turn the pile every 1–2 weeks to add oxygen and speed decomposition
- A pile that doesn’t heat up needs more nitrogen (greens) or more moisture