Compost C:N Ratio Calculator

How It Works

Composting is really just managing the balance between carbon-rich "browns" and nitrogen-rich "greens." The ideal ratio is about 25-30 parts carbon to 1 part nitrogen. Get this right and your compost will heat up, break down quickly, and smell earthy rather than rotten.

Tips

• The classic rule of thumb is 3 parts brown to 1 part green by volume — this gets most people close to the ideal range.
• If your pile smells bad (like ammonia), it has too much nitrogen — add more browns like dry leaves or shredded cardboard.
• If your pile is not heating up or breaking down, it probably needs more greens (nitrogen) or more moisture.
• Chop or shred large pieces before adding them — smaller pieces decompose much faster.
• Turn your compost every 1-2 weeks to add oxygen. A well-aerated pile breaks down 2-3 times faster than one left alone.
• Coffee grounds are technically "green" (nitrogen-rich) even though they look brown — a common source of confusion.