Compost Bin Size Calculator Australia: What Size Compost Bin Do I Need?
Tell us how many people live in your home, how much you cook and how much garden waste you have. We’ll estimate the bin size you need for a cold bin, hot batch or tumbler.
Your compost bin recommendation
How the three methods compare for you
| Method | Size to aim for | Time to compost | Fit |
|---|
Tips for your setup
This is an estimate based on typical figures. Your real needs will depend on what you add, how you manage the heap and the weather.
Choosing a compost bin size in Australia
The right compost bin size depends on how much material you add and how long it takes to break down. A bin that’s too small overflows or can’t build up enough material to work well. One that’s too big can stay half empty, dry out and break down slowly. Matching the bin to your household and garden helps you get usable compost without the mess.
Greens and browns
Kitchen scraps and fresh clippings are “greens”. Dry leaves, shredded paper, cardboard and straw are “browns”. A rough guide is about two parts browns to one part scraps by volume.
Moisture and air
Compost should feel like a wrung-out sponge. Too wet and it turns smelly, too dry and it stalls. Turning or mixing adds air.
Hot, dry weather
In hot, dry parts of Australia, put the bin in part shade, add water when it dries out and keep a lid on it to hold moisture.
Keeping pests out
Use a lid or enclosed bin, bury scraps in the middle and avoid meat, dairy, oils and cooked food, which can attract rats and mice.
Compost bin size by household
| People in household | Kitchen scraps only | Kitchen scraps plus moderate garden waste |
|---|---|---|
| 1 | about 150 L | about 660 L |
| 2 | about 300 L | about 810 L |
| 3 | about 460 L | about 960 L |
| 4 | about 610 L | about 1,120 L |
| 5 | about 760 L | about 1,270 L |
| 6 | about 910 L | about 1,420 L |
For a cold (add-as-you-go) bin in a mild climate, with average kitchen scraps (3 L per person per week) and browns added. Larger totals can be split across two or more bins. Use the calculator above for your own figures.
How this calculator works
We estimate the volume of material you add each week, then work out how much of it is in the bin at any time. The assumptions are simplified:
- Kitchen scraps are about 1.5 L, 3 L or 5 L per person per week, depending on how much you cook.
- You add roughly two parts browns for every part of kitchen scraps.
- Garden waste is estimated at 0, 10, 30 or 60 L a week averaged over the year.
- Material shrinks as it breaks down, so a continuous bin holds about 65% of the raw volume added during the composting time.
- Cold composting is assumed to take about 20, 26 or 36 weeks in warm, mild or cool climates. Hot batches work best at about 1 m³. Tumblers are sized to fill in about four weeks and loaded to three-quarters full.
- Finished compost is about 35% of the raw volume.
Frequently asked questions
What size compost bin do I need?
It depends on your household, how much you cook and how much garden waste you add. Under the assumptions above, a household of three or four with only kitchen scraps often suits a bin of roughly 400 to 600 litres. If you also add a lot of lawn clippings and prunings, you may need around a cubic metre or more, which can be split across two bins or a bay system.
How long does compost take to make?
A cold bin typically takes several months to a year, and it’s faster in warm weather. A well-managed hot compost pile can be ready in around two to three months. Tumblers often finish a batch in roughly six to ten weeks once you stop adding material. Times vary with temperature, moisture and the mix of ingredients.
What shouldn’t I put in a home compost bin?
Meat, fish, dairy and oils can cause smells and attract pests, and dog and cat droppings aren’t suitable for most home bins. Avoid diseased plants and weeds that have gone to seed unless you run a hot pile. Rules and advice differ between councils, so check your local guidance.
Should I choose a compost bin, tumbler or worm farm?
A static bin suits most households and handles garden waste. A tumbler is tidy and faster for batches but holds less. A worm farm is great for small households or apartments, since it handles smaller amounts of kitchen scraps but not garden waste. Some people use a bin and a worm farm together.
How do I keep rats and mice out of my compost?
Use a bin with a lid and a solid base or fine mesh, bury fresh scraps in the middle of the pile, and keep meat, dairy and cooked food out. Keep the heap moist and turned, and don’t leave food scraps exposed on top.
Brought to you by Garden Yard Australia, your Australian garden and outdoor living store.
Results are estimates based on typical figures and will vary with your materials, management and climate.