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Maplestory Ied Calculator

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In the world of MapleStory, battling tough bosses is a major highlight. But to defeat these formidable foes, players need to get past their high defense stats. That’s where Ignore Enemy Defense (IED) comes into play. The MapleStory IED Calculator is a handy tool designed to help players figure out how much of a boss’s defense they can ignore, making it easier to land powerful blows.

Purpose and Functionality of the IED Calculator

IED is a critical stat in MapleStory, allowing players to bypass a portion of an enemy’s defense. However, calculating your effective IED isn’t as simple as adding up all your IED sources because of how they stack multiplicatively, not additively. The IED Calculator simplifies this process by using a special formula to combine IED from various sources, like skills, equipment, and link skills, to give you a clear picture of your total effective IED.


In MapleStory, IED stands for Ignore Enemy Defense. It’s a stat that helps your character deal more damage to enemies with high defense. The calculation for the effective IED can be a bit complex due to the way multiple sources of IED stack with each other. However, I’ll explain it in simpler terms:

  1. Start with Each Source: Think of each source of IED as a separate chance to bypass enemy defense. If you have multiple sources of IED from your skills, equipment, and buffs, list them all out separately.
  2. Convert Percentages to Decimals: Change each IED percentage into a decimal form. For example, 30% IED becomes 0.30.
  3. Calculate Combined Effect: To combine multiple IED sources, you multiply their inverse chances of not ignoring defense. For each source of IED, calculate 1 minus the IED decimal. Then, multiply these values together.
  4. Subtract from 1: After multiplying the inverse chances together, subtract the result from 1 to get the combined IED effect.
  5. Convert Back to Percentage: Multiply the final decimal by 100 to convert it back to a percentage. This is your effective IED against enemy defense.

Example Formula in Simple Words

  • If you have three IED sources of 30%, 20%, and 10%, first convert them to decimals (0.30, 0.20, 0.10).
  • Then, calculate the chance of not ignoring defense for each (0.70, 0.80, 0.90).
  • Multiply these chances together (0.70 × 0.80 × 0.90).
  • Subtract the result from 1 to find the combined IED effect.
  • Convert this final decimal back to a percentage to get your effective IED.

How the IED Calculator Works

The calculator uses a formula that stacks your IED sources in a way that reflects their actual impact in the game. Here’s a simplified explanation:

  1. Gather Your IED Sources: List out all the different places you’re getting IED from, like skills or equipment.
  2. Input the Percentages: Enter the IED percentages into the calculator. Remember, these should be in decimal form (so 30% becomes 0.30).
  3. Calculate: The calculator multiplies the inverse of these decimals, subtracts the result from 1, and gives you an effective IED percentage.

Step by Step Example

Let’s say you have three IED sources:

  • Skill 1 gives you 30% IED.
  • Skill 2 provides 20% IED.
  • An equipment piece offers 10% IED.

To find your effective IED, the calculator does the following:

Effective IED=1−(1−0.30)×(1−0.20)×(1−0.10)Effective IED=1−(1−0.30)×(1−0.20)×(1−0.10)

This calculation results in an effective IED of approximately 49.6%, meaning you’d ignore nearly half of the enemy’s defense when attacking.

Relevant Information Table

Here’s a quick reference for typical IED sources and their ranges:

SourceIED Range
Skills10% – 40%
Link Skills10% – 15%
Equipment5% – 35%
Character Cards1% – 5%


The MapleStory IED Calculator is more than just a tool; it’s a game-changer for players looking to optimize their damage output against high-defense bosses. By accurately calculating your effective IED, you can tailor your gear and skill choices to maximize your effectiveness in battle. Whether you’re a casual player looking to improve or a hardcore gamer aiming for the top, understanding and utilizing your IED can significantly enhance your MapleStory experience.

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