What does expected attempts mean?

Expected attempts is the statistical average number of tries needed for one success. With a 10% chance, you need 10 attempts on average. However, 37% of players will still need more than 10 attempts due to the distribution of random outcomes.

Why did I fail 20 times at 10%?

That's unlucky but not unusual. The probability of failing 20 consecutive times at 10% is 0.9^20 = 12.2%. About 1 in 8 players will experience this, so it's far from impossible.

Does past failure affect future attempts?

In pure random systems, no — each attempt is independent. However, many games implement pity systems or failstacks that genuinely increase your success rate after consecutive failures.

How do failstacks work?

Failstack systems increase the success chance with each consecutive failure, guaranteeing eventual success. If your game has failstacks, the effective expected attempts is lower than the base formula suggests.

Should I buy or enchant?

Compare the expected cost to enchant (attempts × cost per attempt) with the market price of the already-enchanted item. Include the value of your time. If buying is similar cost or cheaper, buy instead.

What is the chance of succeeding in exactly 1 try?

The chance of succeeding on the first try equals the base success rate. For a 15% enchantment, you have exactly a 15% chance of one-tapping it.

Enchantment Probability Calculator

Calculate expected attempts for successful enchantment. Enter success chance to find expected tries, cost, and probability of success by attempt N.

Success Chance per Attempt

Cost Per Attempt

Check After N Attempts

Expected Attempts to Succeed

6.7

Median: 5 attempts

P(Success within 10 tries)

80.30%

Failure chance: 19.7%

Expected Total Cost

3,335 gold

Average across all outcomes

Success Probability Bars

Succeed in 10 tries

80.3%

Fail in 10 tries

19.7%

Cumulative Success Probability Table

Attempts

Success %

Total Cost

15%

500

27.8%

1,000

38.6%

1,500

47.8%

2,000

55.6%

2,500

62.3%

3,000

67.9%

3,500

72.8%

4,000

76.8%

4,500

80.3%

5,000

83.3%

5,500

85.8%

6,000

87.9%

6,500

89.7%

7,000

91.3%

7,500

92.6%

8,000

93.7%

8,500

94.6%

9,000

95.4%

9,500

96.1%

10,000

Key Metrics

Success per $500

15%

Expected Attempts

6.67

Planning notes, formulas, and examples

About the Enchantment Probability Calculator

Enchanting, enhancing, or fortifying gear is a staple of RPGs and MMOs — but the success rates can be punishingly low. This calculator helps you understand the probabilities and plan accordingly.

Given a success chance per attempt, it calculates the expected number of attempts needed, the probability of succeeding within N attempts, and the estimated cost based on materials per attempt. Whether you're enchanting in Black Desert Online, upgrading in MapleStory, or enhancing in Lost Ark, these numbers help set realistic expectations.

Understanding enchantment probability prevents frustration and poor decision-making. Knowing that a 10% success rate requires an average of 10 attempts — and that there's still a 35% chance of not succeeding after 10 tries — keeps you grounded.

Use the estimate as a planning baseline and adjust it once you have real session data from the game you are playing.

When This Page Helps

Players routinely underestimate how many attempts low-probability enchantments require. A 15% chance feels like it should succeed in a few tries, but the expected attempts is 6-7, and bad luck streaks are common. This calculator replaces gut feelings with actual math.

How to Use the Inputs

Enter the success chance per attempt as a percentage.
Optionally enter the cost per attempt (materials, gold, etc.).
Optionally enter the number of attempts to see cumulative probability.
View expected attempts, estimated cost, and probability curves.

Formula used

Expected Attempts = 1 / (Success Chance / 100)
P(success within N attempts) = 1 − (1 − Success Chance / 100) ^ N
Expected Cost = Expected Attempts × Cost Per Attempt

Example Calculation

Result: ~6.67 expected attempts

With 15% success chance: Expected = 1 / 0.15 ≈ 6.67 attempts. Probability within 10 attempts: 1 − 0.85^10 = 80.3%. Expected cost: 6.67 × 500 = 3,333.

Tips & Best Practices

Expected attempts is an average — actual results vary widely due to randomness.
For very low success rates (<5%), budget for 2-3× the expected attempts.
Some games offer pity or failstack systems that increase success rate after failures.
It's not uncommon to take 2× or 3× the expected attempts — that's just probability.
Consider whether buying an already-enchanted item is cheaper than enchanting yourself.
Never enchant with materials you can't afford to lose.

The Mathematics of Enchanting

Enchantment success follows a geometric distribution. The expected number of trials is 1/p where p is the probability. But the distribution has a long tail — while the average might be 10 attempts, some players will need 30 or more.

Planning Your Enhancement Budget

Always prepare for the worst reasonable case, not the expected case. If expected attempts is 10, budget for 20-25 attempts worth of materials. Running out of materials mid-enhancement is frustrating and can lock you into a worse position.

Pity Systems and Guaranteed Success

Modern games increasingly implement pity mechanics that guarantee success after a maximum number of failures. These systems cap the expected cost and prevent extreme outlier experiences, making enhancement more predictable and less punishing.

Sources & Methodology

Last updated: February 10, 2026

Frequently Asked Questions

Expected attempts is the statistical average number of tries needed for one success. With a 10% chance, you need 10 attempts on average. However, 37% of players will still need more than 10 attempts due to the distribution of random outcomes.