# Etrian Odyssey II: Heroes of Lagaard

## byDr. Fetus

### Part 7: Game Mechanics - Formulas

Game Mechanics: Formulas

This is going to be a number heavy update, so if you don't like math for some reason, too bad! Etrian Odyssey uses a ton of formulas to calculate things, most of which change from game to game. I will provide a short explanation of what the formulas actually do, and what actually has an effect. The formulas you see here only apply to EO2, they do not apply to the other games.

The damage formula for STR based attacks is as follows:

#### Party's Damage and Defense Formulas posted:

Attack = (attacker's STR + [weapon ATK / 6]) * (20 + attacker's STR) * (20 + [weapon ATK / 3])
Party Defense = (20 + defender's VIT) * (20 + equipment defense)
Base Damage = [[Attack / Monster Defense] * 1.7]

If Base Damage < 5, then add a random number from 1 to 5.
If Base Damage > 5, then add 10 * [Base Damage / 100]

Anything in brackets is rounded down. Basically, increasing the STR stat has much more of an effect than upgrading weapons. This does NOT apply to the later EO games, where increasing STR has far less of an effect.

Monsters can't use weapons or armor, so these formulas apply to them instead.

#### Monster Damage and Defense formulas posted:

Attack = (attacker's STR + [attacker's STR / 6]) * (20 + attacker's STR) * (20 + [attacker's STR / 3])
Monster Defense = (20 + defender's VIT) * (20 + defender's VIT)
Base Damage = [[Attack / Party Defense] * 1.7]

If Base Damage < 5, then add a random number from 1 to 5.
If Base Damage > 5, then add 10 * [Base Damage / 100]

Then multiply the final result by 0.8.

The main difference here is that their STR and VIT stats are applied to the variables that need equipment. What this formula means is that monsters do far less damage to the party than the party can do to them. Both of these final results are then run through damage modifers of skills if they are used, and then the target's resistances. It's also very important to keep your defensive equipment up to date, although defensive equipment don't have as big of an increase in numbers than weapons.

Now TEC based attacks follow a slightly different formula. Although the Alchemist is the only class that can actually use TEC based attacks. The formula for those are as follows:

#### Party TEC Damage and Defense Formula posted:

Attack = (attacker's TEC + [Spell Power / 2]) * (20 + attacker's TEC) * (20 + Spell Power / 2)
Party Defense = (20 + defender's TEC) * (20 + equipment defense)
Base Damage = [[Attack / Monster Defense] * 1.7]

If Base Damage < 5, then add a random number from 1 to 5.
If Base Damage > 5, then add 10 * [Base Damage / 100]

It's basically a modified version of the weapon attack formula. A couple of monsters are capable of using TEC based attacks, so the formula for those are as follows:

#### Monster TEC Damage and Defense Formula posted:

Attack = (attacker's TEC + attacker's TEC) * (20 + attacker's TEC) * (20 + attacker's TEC / 2)
Monster Defense = (20 + defender's TEC) * (20 + defender's TEC)
Base Damage = [[Attack / Party Defense] * 1.7]

If Base Damage < 5, then add a random number from 1 to 5.
If Base Damage > 5, then add 10 * [Base Damage / 100]

Then multiply the final result by 0.8.

This one actually isn't too different than the monster's attacking formula. It's the same result in the end, monster attacks do far less damage than what your party can dish out. The final results are then run through damage modifiers (Monsters only) and then the target's resistances.

Accuracy uses the same formula for both your party and the monsters.The accuracy formula is as follows:

#### Accuracy Formula posted:

BaseAccuracy * (1 + attacker's AGI * .01 + attacker's LUC * .005) = ModifiedAccuracy

[ModifiedAccuracy / (1 + defender's AGI * .01 + defender's LUC * .005)] = ActualAccuracy

ActualAccuracy * [AccuracyModifiers] = Final Accuracy

Final Accuracy is then capped between 20% to 100% inclusive. AccuracyModifiers refer to any buffs and debuffs, which are multiplied among st themselves before being applied to the formula. Now if the attacker has their head bound, the Final Accuracy is then multiplied by 0.8. If the attacker is blind, then the Final Accuracy is multiplied by 0.25. Now if a Ronin has the Shiraha ability, that's factored in after all the calculations. Since it applies a 30% evasion bonus at the maximum level, the final result would be multiplied by 0.7.

Now this formula applies to STR based attacks. For TEC based attacks, just replace all instances of AGI with TEC. Each point of AGI and TEC adds 1% to accuracy and evasion to their respective formulas. Each point of LUC only increases the accuracy and evasion by 0.5%, but it applies to both STR and TEC based attacks.

The healing formula is as follows:

#### Heal Formula posted:

[[Heal Power * (160 + user's TEC) / 160] * Mastery Bonus]

A pretty simple one. What this formula means is that each point of TEC gives you an extra 0.6125% healing, up to 60.6375% bonus healing at 99 TEC.

There's also a formula that determines your chance of recovery from a status effect. The formula for that is as follows:

#### Status Recovery Formula posted:

Base Chance * ((10+LUC)/(3*LVL)) = Recover Chance

The Base Chance depends on the status or bind that has been inflicted. Those would be:

Sleep: 40%
Paralysis: 40%
Confusion: 30%
Terror: 30%
Poison: 25%
Everything else: 20%

Basically, it takes longer to recover from binds than status effects. And the more you level up, the longer it takes to recover from said status effects. It's a trade off for leveling up, since it's harder to inflict status effects on someone who has a high LUC stat. This applies to both your party and the enemies. Enemies have levels too, although unlike the first game, it doesn't reduce or increase the amount of damage you can deal or take from them.

Now, for every turn that passes, including the turn the ailment or bind was first inflicted, an additional 10% is added onto the final result. Now the Troubadour's Recovery song actually factors into that value. The recovery rate is added directly onto the additional 10%, meaning that you only need 3 levels in that skill, unless you want to increase the speed modifier of that skill by a measly 20% from level 1 to 2.

Unfortunately, I do not have the formula for the chances of inflicting status effects and binds. All I know is that it only uses the LUC stats of the attacker and the defender, and that it doesn't have that much of an effect on the final chance anyways unless the LUC difference is massive.

And before I forget to mention this, take a look at the screenshot below.

See those attack and defense numbers? Those are complete and utter nonsense. Those numbers aren't used in any formulas at all. They're just an estimate of how hard you'll hit and get hit. You have to look at the actual stats of the equipment in order to figure out how much damage you can take and dish out. And yes, this applies to every EO game, except for EO1. Those numbers are completely meaningless, and I'm not even sure why those are there, other than to confuse the player some more.