Compost Volume Reduction Calculator

Smart tools for smarter gardening. Calculate exactly how much your compost will shrink as it breaks down – no guesswork needed!

Compost Shrinks As It Decomposes!

Use this tool to estimate how much volume you’ll lose over time. Perfect for planning bin space or harvest schedules.

Gardener Tip: “For fastest decomposition: Turn pile weekly + maintain 50% moisture.

Estimate how much your compost will shrink as it decomposes.

Initial Compost Volume (gallons):

Decomposition Timeframe:

How it works: Compost volume reduces as organic matter breaks down. Typical reductions are 50% (3 months), 70% (6 months), or 90% (12 months) under optimal conditions.

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Compost Volume FAQs

Why does compost volume reduce?

Microorganisms break down organic matter, releasing CO2 and water. This process can shrink volume by 50-90%.

How accurate is this calculator?

Estimates assume optimal conditions. Actual results vary based on moisture, temperature, and materials used

When is compost ready to use?

When it’s dark brown, crumbly, and smells earthy (usually 3-12 months).