Arcane Lineage doesn’t appear to have a single fixed “day length” officially spelled out in the sources I found, so the safest answer is that it’s treated like a normal day/night cycle in play rather than a specially defined lore value. Community discussion also seems to focus on in-game timing mechanics and quests, not a confirmed real-world duration for each day.

What that means

  • In practice, players usually mean the game’s day-night cycle, not a canon measurement.
  • I didn’t find a reliable official statement giving an exact number of minutes per day.
  • Forum and guide content points to gameplay usage of “daily” tasks and time-based quests, but not a published day length.

Best practical answer

If you’re asking how long one in-game day lasts, it’s best described as “a standard Roblox-style cycle with no clearly documented official duration.” If you want, I can also help narrow it down by checking whether you mean the day-night cycle , a daily reset , or a quest timer.