Question 1

What is the ideal carbon-to-nitrogen (C:N) ratio for compost?

Accepted Answer

The ideal compost C:N ratio is about 30:1 by mass. Browns (dry leaves, straw, paper, cardboard) supply carbon, while greens (food scraps, grass, coffee grounds) supply nitrogen. A 3:1 to 4:1 volume ratio of browns to greens usually lands near the 30:1 target.

Question 2

How big should my compost bin be?

Accepted Answer

A household compost bin should hold at least 1 cubic yard (27 ft³ / 750 L) so the pile can retain heat, but no larger than 5 cubic yards or it becomes hard to turn. A 3×3×3 ft bin (27 ft³) is the most popular home size.

Question 3

How much compost do I need for my garden?

Accepted Answer

Most gardens benefit from a 1–2 inch (2.5–5 cm) layer of compost worked into the topsoil each year. One cubic yard covers about 324 ft² at 1 inch deep. The calculator shows the exact volume you need from your bin or pile dimensions.

Question 4

Does this calculator account for compost settling?

Accepted Answer

Yes. Compost loses roughly 40–60% of its volume as the materials decompose. The calculator reports both the raw bin volume and the expected finished compost yield so you can plan how much to harvest.

Composting tips