Crafting Success Rate Calculator
Many games feature multi-step crafting systems where each step has its own success rate. The overall success probability is the product of all per-step rates. This calculator accepts up to 6 crafting steps, each with a success probability, and computes the combined overall probability. It also shows the expected number of attempts needed to produce one successful item. Use it to balance crafting recipes and plan material requirements.
Enter success rate (%) for each crafting step. Leave unused steps blank.
Multi-step crafting success formula
Overall P = p(1) * p(2) * ... * p(n)
Expected attempts = 1 / Overall P
where p(i) = step i success rate as a decimal
Each step is assumed to be independent. Failing any step means the whole craft fails (starting over). This is the multiplication rule for independent events.
Crafting balance in game design
- Three steps at 90%, 80%, 70% give 50.4% overall success, meaning roughly half of all attempts will complete successfully.
- Adding a fourth step at 60% drops overall success to about 30%, doubling the expected material cost compared to three steps.
- Designers tune individual step rates so the overall success probability matches the intended rarity and material sink for the crafted item.
- Guaranteed steps (100% success) do not affect the product and can be freely added without changing probability, useful for flavor steps in crafting UI.
Crafting success rate: frequently asked questions
How is multi-step crafting success probability calculated?
For independent steps, the overall success probability is the product of each step's success rate. If step 1 succeeds 80% of the time and step 2 succeeds 70% of the time, the overall probability is 0.8 times 0.7, which equals 0.56 or 56%.
What is the expected number of attempts to complete a craft?
Expected attempts = 1 / overall success probability. At 56% overall success, you expect about 1.79 attempts on average before the complete craft succeeds.
What if a failed step wastes materials?
In that case, expected material cost = expected attempts times materials per attempt. If each attempt uses 3 materials and you expect 1.79 attempts, you need an average of about 5.4 materials to complete one successful craft.
How does adding more steps affect the overall probability?
Each step multiplied in reduces the overall probability. Even steps that are individually likely (90% each) compound quickly: 10 steps at 90% each gives only 34.9% overall success. Game designers must balance step count with per-step rates carefully.
Can this be used for crafting systems in tabletop RPGs?
Yes. Many tabletop RPG crafting rules require multiple skill checks, each with its own DC and probability. Enter each step's success probability to find the combined probability of a complete craft succeeding.
Official sources
- NIST/SEMATECH e-Handbook of Statistical Methods: itl.nist.gov/div898/handbook/.
- National Council of Teachers of Mathematics: nctm.org.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.