Work out composting time instantly with clear inputs, formula shown and shareable results.
The estimate starts from eight weeks for an ideal 30:1 pile turned weekly, penalising deviation from that ratio, longer intervals between turnings and piles under three quarters of a cubic metre. Piles smaller than about a cubic metre cannot hold heat, which is why a small bin composts far more slowly than the same material in a large heap.
Time estimate
weeks = 8 x C:N penalty x turning factor x size penalty
Volume reduction
finished volume is about 40% of the starting volume
weeks = 8 x C:N penalty x turning factor x size penalty. The estimate starts from eight weeks for an ideal 30:1 pile turned weekly, penalising deviation from that ratio, longer intervals between turnings and piles under three quarters of a cubic metre.
Piles smaller than about a cubic metre cannot hold heat, which is why a small bin composts far more slowly than the same material in a large heap.
Enter carbon to nitrogen ratio, days between turnings, pile volume. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.