Minecraft Composter Calculator
Editions: Java + Bedrock (chances shared — one Bedrock-only item, see FAQ) · Verified: Java 26.3 / Bedrock 26.50 · 2026-09-16 · Updated 2026-09-19
A composter takes 7 levels of compost and hands back one bone meal. What it costs you depends entirely on which item you feed it, and on one rule most guides skip: the first item into an empty composter always lands. Pick an item to see what a stack really returns, or name a bone meal target and get the pile it takes.
Items to bone meal
Bone meal goal
How much of each kind of item a target takes, if you are deciding what to farm for it.
The worked example
A wheat farm is the usual reason to build a composter. Wheat composts at 65%, so one bone meal costs 1 + 6 ÷ 0.65 = 10.23 wheat on average, and a full stack of 64 returns 6.26 bone meal. Feed the composter the seeds instead and the picture changes hard: seeds sit at 30%, which is 21 items per bone meal, so the same stack gives 3.05. The seeds are still worth composting, because a wheat farm produces them whether you want them or not, but a stack of them is worth less than half a stack of wheat.
Two items break the pattern in your favor. Melon slices compost at 50% and melon blocks at 65%, which makes the block look better until you count the crafting: the nine slices that make one block return 0.69 bone meal against the block's 0.10, about seven times as much, so never craft melons up before composting them. Cookies go further. One recipe of 2 wheat and 1 cocoa beans yields 8 cookies at 85%, worth 0.99 bone meal, where composting those 2 wheat directly returns 0.20 — roughly five times the return for one crafting step.
The five chance tiers
| Composting chance | Items per bone meal | Bone meal per stack of 64 | Items for 64 bone meal |
|---|---|---|---|
| 30% | 21.00 | 3.05 | 1,344 |
| 50% | 13.00 | 4.92 | 832 |
| 65% | 10.23 | 6.26 | 655 |
| 85% | 8.06 | 7.94 | 516 |
| 100% | 7.00 | 9.14 | 448 |
The 7 levels, the always-lands first item, the five chance tiers and the formula come from the Minecraft Wiki's composter page, read 2026-09-16, and were checked item by item and tier by tier against the composter calculator at minecraftmaps.com/tools/composter-calculator, which agrees on every number this tool computes with. The composting guide shows the working.
Questions builders actually ask
How many items does it take to fill a composter?
On average 1 + 6/p, where p is the item's composting chance. A composter holds 7 levels, and the first item added to an empty one always lands whatever its chance, so only the remaining 6 levels are left to luck. At 65% that is 10.23 items per bone meal, at 30% it is 21, and at 100% it is exactly 7.
Why is the answer not just seven divided by the chance?
Because the first layer is free. Seven divided by the chance would assume every one of the 7 levels is a coin flip, but the first item added to an empty composter always raises the level. That is worth more at low chances than high ones: at 30% it cuts the average from 23.3 items to 21, while at 100% it changes nothing.
Which items are worth composting?
The small ones, and the ones you have too many of. Smaller pieces usually beat the blocks they craft into: the nine melon slices that make one melon block return about seven times the bone meal the block would. Cookies are the standout, because one recipe of 2 wheat and 1 cocoa beans makes 8 of them, which is about five times the bone meal that composting the 2 wheat directly would give.
Do Java and Bedrock composters behave the same?
The 7 levels, the free first layer, the five chance tiers and the formula are the same in both. The item lists differ in one place: the grass block is compostable at 30% in Bedrock only, which the Minecraft Wiki records as MCPE-140266.
Why is the straw bed missing from the item list?
Because the two sources this page is checked against do not agree on it. The Minecraft Wiki lists the straw bed at 65%, while the composter calculator at minecraftmaps.com lists it at 85%. It is a new item in the 26.3 drop, and until both say the same thing it gets no tier here.