Compost Volume Calculator

Compost Q&A Guide

How do I calculate how much compost I need?

To calculate compost quantity, measure the area you want to cover (length × width), then multiply by the desired compost depth. Convert all measurements to the same unit (e.g., meters). Multiply area by depth to get volume, and then convert to liters or cubic meters. Use: Volume = Area × Depth.

How many kg is 40 Litres of compost?

Compost density varies, but a typical value is about 0.4 to 0.6 kg per liter. So, 40 liters ≈ 16–24 kg. Check your compost bag for precise density or moisture content, as these affect weight significantly.

How do you calculate compost ratio?

The ideal compost ratio is about 30:1 carbon-to-nitrogen (C:N). Carbon-rich materials (browns) like leaves or cardboard are balanced with nitrogen-rich materials (greens) like food scraps. To calculate, estimate weight or volume of C and N components and balance according to the ratio.

How many litres of compost per m²?

For a 1-inch (2.5 cm) layer, use roughly 25 liters per m². For deeper layers, multiply proportionally. Example: for 5 cm depth → 25 × 2 = 50 L/m².

How many kg is 20L compost?

Using average density (0.5 kg/L), 20 liters of compost weighs about 10 kg. Lighter, drier compost may weigh less; moist, denser compost more.

How much compost per square meter?

It depends on your soil needs and planting type. A general recommendation is 50–100 liters per m² for enriching soil. Lighter top dressing may require only 25 L/m².

How much is 1 cubic meter of compost?

1 cubic meter is equal to 1,000 liters. In weight, it typically ranges between 400–600 kg depending on compost density and moisture.

How many litres are in 1 tonne of compost?

Compost varies in density. Assuming an average of 0.5 kg/L, 1 tonne (1,000 kg) equals approximately 2,000 liters. Heavier compost would be less in volume.

How do you measure compost?

Compost is measured by volume (liters, cubic meters) or weight (kilograms, tonnes). Gardeners often use volume for applications (e.g., per m²), while suppliers may label bags by liters or kg.

What is the perfect compost ratio?

The ideal composting ratio is 30:1 C:N (carbon to nitrogen). This ensures active decomposition and odor control. Examples: dry leaves (carbon) mixed with kitchen scraps (nitrogen) in the right balance speeds up composting and avoids rot.

How can you tell if compost is good quality?

Good compost is dark brown or black, has a rich earthy smell, and is crumbly. It should be free from visible food or waste chunks, and moist but not wet. A soil test can confirm nutrient content for professional use.

Why is compost measured in litres?

Compost is commonly sold and applied by volume, especially for gardens and containers. Litres (or cubic meters) provide a practical way to measure how much compost will cover an area at a given depth.