Armor and damage absorption formulas

Here is the armor formula for London 2038.

1. Armor formula

Definitions:
A = armor, as shown on the character screen.
DA = Damage absorption, as shown on the character screen.
K(L) = A formula based on character level. The formula is K(L) = 20*L + 80.

If you look at your character screen, you will see that
DA = A / (A + K(L)).
Try it. You’ll see that the formula shows you what you see in game.

Someone posted this formula to the original game’s forum, forums.hellgatelondon.com. In the original game, K(L) was 5*L + 20, and likewise, armor values were 1/4 of what they are now.

When A = K(L), DA = 50%. K(L) is the amount of armor you need to give you 50% damage absorption. At level 50 this is 1080.

Solving for A in the armor formula tells you how much armor you need to get a certain DA:
A = K(L) * (DA / (1 - DA)).

2. Effective health

Definitions:
H = health (total health, including all health bonuses).
E = effective health; the amount of incoming damage you can take before dying.

The meaning of the term “damage absorption” is that
E = H / (1 - DA).
For example, if DA = 75%, E = H / (1 - 0.75) = H / 0.25 = 4 * H. Your 75% damage absorption reduces all damage to 1/4 of its original value, so you can take 4 times as much damage before dying.

3. Armor required for effective health

If you plug in the armor formula to the effective health formula and simplify the expression, you’ll see that
E = H (1 + (A / K(L))).

The effect of armor on your effective health is linear. Every time you add K(L) more armor, you increase your effective health by 100% of H, your health. When A = K(L), that’s easy to see, because your DA = 50%. You absorb half of incoming damage, doubling your effective health.

Here are some values of A, DA, and E.
The character screen rounds DA down to the nearest percent.

                      Effective
   Armor      DA       Health 
----------    ---     ---------

1/4 * K(L)    20%     125% * H
1/2 * K(L)    33%     150% * H
3/4 * K(L)    42%     175% * H

  1 * K(L)    50%     200% * H
  2 * K(L)    66%     300% * H
  3 * K(L)    75%     400% * H
  4 * K(L)    80%     500% * H
  5 * K(L)    83%     600% * H
  6 * K(L)    85%     700% * H
  7 * K(L)    87%     800% * H
  8 * K(L)    88%     900% * H
  9 * K(L)    90%    1000% * H

4. Level scaling

This is kind of a technical footnote.

The main thing to understand in this section is that damage is affected by hidden factors, one of which is the level of the attacker.

When the person posted the armor formula, they said the character level L is actually the attacker’s level, rather than the defender’s level. That means the higher the attacker’s level, the more armor you need to get the same damage absorption. What the character sheet shows is the value of DA for an attacker of your own level.

I don’t know how that person got that information, nor whether it’s true, but I do know another piece of evidence that the game uses the attacker’s level to scale damage. Another thing posted to the original forum was a spreadsheet named monsters.xls containing game data that someone said they got via reverse engineering. One tab in monsters.xls was “Scaling for level diff”, a table of scaling values based on the relative levels of the attacker and defender, and on whether the attacker was a player or a monster. For example, for a player attacking a monster 11 or more levels higher than the player, the table showed a scaling factor of 1%, a huge reduction in damage.

My guess is that both of those level-based scaling factors were in effect in the original game. They’re probably in 2038 too.

So you might imagine that, say, Shulgoth has 100 Health and 80% damage absorption, and it’s easier for higher level characters to kill him because their weapons and skills do more damage. But the game actually applies a lot of complicated scaling to the numbers it shows you.

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Hi, thanks for this. I’ve often wondered about this myself. Is there like a calculator app for this somewhere? I sometimes get lost in all this math, so calculators would be great. Thanks again for putting the research on this.

You’re welcome! There’s no calculator app.

You can always make it yourself using MC Excel or Google Sheets and leave all the math to them.

Here’s an application of the armor and effective health formulas to a comparison of Venom Armor and Darkform, asking “if want to max one or the other, which one is better?”

Let’s assume this is the baseline character:

  • Base health 1000 from stamina
  • Base armor ~1000, giving ~50% damage absorption, or a 200% multiplier to heath.
  • +1 all skills helmet
  • 1 skill point in Darkform, for a total of Darkform 2 (+30% health; Darkform 1 gives +25% health and every rank after that gives another +5%.)
  • Enhanced Stamina 2 (+ ~10% health. It’s actually 8%, but I’m rounding it up to 10% to keep it simple. You might have a larger total health bonus anyway, either from more ranks in Enhanced Stamina or from gear affixes).

So effective health is 1000 x 140% x 200% = 2800.

Typically you take Venom Armor all-or-nothing, so that if you have it, you can keep it on all the time. The baseline character needs 8 skill points to get it to rank 9 where the base duration matches the base cooldown of 60 seconds. That provides ~500 armor, or another ~50% to the armor multiplier.
Then effective health is 1000 x 140% x 250% = 3500.

Instead, you could spend the same 8 skill points on Darkform, adding another +40% health bonus.
Then effective health is 1000 x 180% x 200% = 3600.

They’re about the same. The more health bonuses the character starts with, the better Venom Armor is; the more armor the character starts with, the better Darkform is.

If you take both, effective health is 1000 x 180% x 250% = 4500.

Of course, there are other things that make Venom Armor and Darkform different. Venom Armor is a more active skill, with a damage behavior, and it’s part of a skill tree. And even health and armor don’t behave exactly the same. One way in which they’re different is that the more armor you have, the easier it is to keep yourself healed, because you take less damage and so you require less healing.

As a footnote, flat health bonuses such as “Hit Points: +300” don’t benefit from health multipliers. So for example if the baseline character had a flat +300 Health bonus,
their effective health would be ((1000 x 140%) + 300) x 200% = 3400.
It would NOT be ((1000 + 300) x 140%) x 200% = 3640.
That would affect the calculations for a character with a flat health bonus.

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