For a level 200 Arcane weapon , the usual estimate is about 10–20 Black Cubes for 2 lines of ATT%, and often 50+ Black Cubes for 3 lines , depending on your luck and tier progression. For 13% ATT + 10 ATT flat , the exact cube count can swing a lot because ATT% and flat ATT don’t come from the same potential pool, so the total can vary widely.

Practical estimate

  • 13% ATT on a weapon is often something you can hit relatively early if you are only chasing one good line, but the cube count is still RNG-heavy.
  • 10 flat ATT is not usually the main thing people aim for on weapon potential; it’s more of a side result while rolling, so it may take noticeably longer than just hitting a %ATT line.
  • If you mean 3 lines of strong ATT potential , a common community expectation is dozens of Black Cubes , not just a handful.

What this means in-game

  • If you’re asking for a rough budget , plan for at least 20–50 Black Cubes for a decent shot at a usable result.
  • If you want something more specific like 13% ATT plus 10 flat ATT on the same weapon , expect more than that because you’re chasing a narrower outcome.
  • RNG can still make it happen much sooner, but it can also take much longer than average.

Short answer

A safe answer is around 20–50 Black Cubes minimum , with 100+ not being crazy if you’re aiming for a very specific weapon potential setup.