Is it okay to copy a game's formula? Formulas like damage formulas, taking the stats STR, DEX, INT, critical rate, etc. into account. Specifically I want to copy Ragnarok Online's damage calculation. But I will probably remove some stuff from the formula to reduce the scope of my game.

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I think game formulas and the like are different from game mechanics. Game mechanics is how the game is played.


2 Answers 2


Yes, that is legal.


  • You may not steal their code, but you are allowed to reproduce what the code does. The code is allowed to end up looking the same, if you can reasonably claim that is wasn't a copy-paste job. See Google vs Oracle.
  • Advertising your game as "using Ragnarok Online's damage formula" can be interpreted as an implied endorsement by, or co-development with, Ragnarok's developers. They can sue you to remove this claim.
  • If they patented any parts of their application, you're liable for license fees on their terms. Even if their patent is fraudulent and should never have been granted, getting a judge to say so is more expensive than paying the license fees. Their design elements might also be patented by someone else, who can then ask you for license fees.
  • They can sue you without having a valid legal case.
  • \$\begingroup\$ You should probably add that you are not a lawyer. You can not really say if it is legal, until someone sues you for it, and a court actually defines it as legal. Other issues like location and precedent play a role. As your own answer says, you can be sued for anything. \$\endgroup\$
    – Gnemlock
    Commented Mar 20, 2017 at 2:24
  • \$\begingroup\$ If I say I copied Ragnarok Online's damage formula, can they still sue me? I mean, "copied" implies that there's no co-development with Gravity (Ragnarok's developers). Anyway, I decided I won't use their calculation just to be safe. \$\endgroup\$
    – Zik
    Commented Mar 20, 2017 at 4:48
  • \$\begingroup\$ @Zik, it is important to remember that if you have the funds and a lawyer willing to take your case, you can sue someone for anything, so can they sue you? Yes. \$\endgroup\$
    – Gnemlock
    Commented Mar 20, 2017 at 8:05
  • \$\begingroup\$ @Zik The last point applies, so they can always sue you, as can Microsoft, EA, Disney, Oracle, and many others. If you can afford a lawyer, they will not succeed at anything other than driving you to bankruptcy due to lawyer fees. In everyday live the second point just means if they ask you to remove that claim, you should comply, despite the claim being accurate. \$\endgroup\$
    – Peter
    Commented Mar 20, 2017 at 13:57

Under normal circumstances, so long as you don't steal their actual game code (i.e. reverse engineer stuff or hack the game's files to get the code) you should be fine. Also, seeing as how this is a community-run wiki, it should be fine to use whatever is inside (unless otherwise specified in the wiki), but being careful is never bad.

This is what's written down on the site (including your page):

Content is available under GNU Free Documentation License 1.3 or later unless otherwise noted.

You can find detailed info about it here and a short explanation here. It basically means you're free to use it however you like.

  • \$\begingroup\$ @Gnemlock The other answer gives unnecessary legal advice in my opinion. The first point is the same as the one I've raised and that's relevant. The second point talks about endorsement and advertising the game as using the other's formula, nowhere in the question is there any indication of that whatsoever. Third point talks about patenting the game's formula which is not a thing. Last point is just irrelevant of the question it's also not true everywhere. It might be the case in the USA but it's definitely not true in Turkey, where you NEED a legal case to be approved to sue someone. \$\endgroup\$ Commented Mar 20, 2017 at 8:30

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