Anvil Calculator — cheapest enchant order
Pick your item, add the enchanted books, and get the provably cheapest combine order — every anvil use, its XP level cost, prior work penalties and "Too Expensive!" warnings. Java edition.
How the anvil math works
- Enchant value — every enchantment has a per-level multiplier; the sacrifice charges level × multiplier for each enchantment it carries. Books use half the item multiplier, which is why you sacrifice books, not gear.
- Prior work penalty — every time a piece survives an anvil its hidden work count rises by 1, and the penalty it adds to future combines is 2work − 1:
| anvil uses survived | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|---|
| penalty it adds | 0 | 1 | 3 | 7 | 15 | 31 | 63 |
- Both sides pay — a combine costs the sacrifice's enchant value plus the target's penalty plus the sacrifice's penalty, and the result's work count becomes max(target, sacrifice) + 1. Because the penalty doubles every use, adding books one at a time gets brutal fast — a balanced "bracket" of book-on-book merges is almost always cheaper.
- The 39 cap — in Survival, any single anvil use over 39 levels reads Too Expensive! and can't be done (Creative ignores it). The plan flags any step that breaks the cap.
- Exact, not heuristic — this tool tries every possible way to bracket your item and books, weighing cheap-now trees against low-work-count trees that pay off later, and returns the true minimum total. (Also available in the Vorla Launcher app as the Anvil Optimizer.)
FAQ
What is the prior work penalty?
A hidden counter on every item and book that goes up by 1 each time it survives an anvil. The penalty it adds to a combine is 2work − 1 levels: 0, 1, 3, 7, 15, 31, 63… Both the target and the sacrifice add theirs, and the result keeps max(both) + 1. Renaming an item also counts as anvil work in older versions — in modern Java, renaming costs 1 level flat and doesn't raise the counter.
Why combine books with books first?
Penalties depend on work counts, so the cheapest plan keeps work counts low on the pieces that get combined most. Merging books in pairs, then pairs of pairs, and finally one big book onto the item (a balanced bracket) usually beats one-at-a-time by a wide margin — the calculator shows you exactly how much you save.
What does "Too Expensive!" mean and how do I avoid it?
Survival anvils refuse any single use costing more than 39 levels. Avoid it by using the balanced order this tool suggests, starting from a fresh (zero-work) item, or settling for one fewer heavy enchant. If even the optimal plan has a step over 39, that combination simply can't be finished in Survival on that item.
Is this Java or Bedrock?
Java edition. Bedrock uses the same prior-work doubling but slightly different enchant multipliers and merging rules, so totals can differ by a few levels. The Java anvil formula has been stable for years, so the plan holds across modern versions.