How is the success rate determined?

Each enchant level has a base success chance that falls as the level rises, then is further reduced by the item tier. The tool shows the per-attempt chance for the next step toward your target, which is the hardest single step on the path.

What does expected attempts mean?

When each attempt succeeds with probability p, the expected number of attempts until the first success is 1 divided by p — the geometric mean. It is an average, so a run may finish faster or slower than the figure shown.

How is the total cost calculated?

The tool sums the expected attempts at each level from your current level up to the target, multiplies each by your per-attempt cost, and adds them up. This gives the average gold to climb the full path, not just one step.

Why does cost rise so fast at high levels?

Success rates shrink at higher enchant levels, so the expected attempts per level grow quickly. Because cost is attempts times price, a few extra levels near the top can multiply your total spend several times over.

Are failures destructive?

This model assumes a failed attempt simply does not advance the level and consumes the attempt cost, which matches most non-destructive enchant systems. If your system can downgrade or destroy the item on failure, real costs will be higher than shown.

Old School RuneScape Enchant & Gear Score Calculator

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Enchanting gear to a high level is a probability climb where each step gets harder and more expensive. This calculator shows the per-attempt success chance, the expected number of attempts, and the average gold to reach your target enchant level.

How it works

Each enchant level has a base success chance that decays as the level rises and is scaled down further by the item tier. Reaching a target level is a sum of independent geometric processes, one per level along the path:

success(level)   = baseChance / (1 + tierPenalty) reduced as level rises
expected attempts(level) = 1 / success(level)
total cost        = Σ expected attempts(level) × cost per attempt

Summing expected attempts from your current level to the target gives the average attempts — and therefore the average gold — for the whole climb.

Example and tips

Pushing a high-tier item from level 7 to level 10 means each step has a low success chance, so expected attempts pile up and the total cost can dwarf the cost of the early levels. Stockpile attempt materials before starting a high-tier push, and stop at the level where the marginal gear score gain no longer justifies the steep climb — the last few levels are almost always the worst value per gold.