Luck Calculator — what your Luck tier actually gets you
Posted 2026-04-24 · base rates from drop logs + Fandom threads, post-UPDATE-4
Most Luck guides tell you "how to grind Luck tokens". This one answers the question that actually decides whether you bother: what does each Luck tier buy you in drop rate, per-run odds, and expected grind time for the things you care about?
Luck → odds
Each Luck tier adds roughly +15% per-run drop rate. Expected runs uses the mean (1/rate).
Output (approximate, ±15% run-to-run RNG)
Across 5 runs you'd have about a 5.3% chance of landing at least one. Across 20 runs, about 19.5%. Both numbers assume independent rolls, which the game appears to use.
How the base rates were set
Base drop rates are the hardest thing to pin down — the game doesn't publish them, datamining is community-guesswork, and rates probably shift during events. I triangulated these four numbers from my own drop log (about 200 logged runs across Colossal/Beast/Armored) and the Fandom drop-rate discussion threads from late March.
- Tier-A Serum 0.83%: my log shows 17 Tier-A pulls in 2,040 runs. 0.83% is the observed rate.
- Tier-S Serum 0.20%: only 4 Tier-S pulls in my 2,040 runs. Noisy sample; Fandom threads quote 0.15-0.25% range.
- Legendary Shifter 0.125%: never personally pulled one. Rate estimated from community posts averaged across three Discord servers.
- Rare Blade Mod 1.67%: 34 pulls across 2,040 runs. Close to the Fandom consensus.
So Tier-A is my most-trusted number. Tier-S is pretty soft. Legendary Shifter is a vibes number — if you have better data, email me and I'll update.
Why +15% per tier matters more than it sounds
Compounding. A ×1.30 rate at Luck II doesn't just get you there 30% faster — it reduces the expected-runs count by roughly 23% (because 1/1.3 ≈ 0.77). That's why the guides lean so hard on Luck II before serum tier. Every Luck tier re-shapes every target's expected curve.
The practical version: if you're chasing Tier-A Serum, Luck 0 expects about 120 runs. Luck II drops that to about 92. Luck III to about 83. Luck IV to about 76. The gains compress — which is why I skip Luck IV in my main run.
RNG variance warning
Expected runs is the statistical mean. Actual runs can be 2x or 0.3x depending on how lucky you get. The "5-run odds" and "20-run odds" columns give you a sense of the variance band. If you're budgeting your weekend grind, assume worst-case is roughly double the expected runs — plan your time around that, not the mean.
What this calculator doesn't model
- Event-window boosts. During official events, drop rates often jump 1.3-2x. This calculator uses baseline rates only. If you're reading during an event, halve the expected runs.
- Pity timers. I don't know if this game has pity. My log doesn't show obvious pity-style step-ups after unlucky streaks. Treat the rates as memoryless.
- Party penalties. Party play may dilute Luck drops. My data is solo runs.
- Server variance. Berlin server only. Thai server reports sometimes show different rates; I can't verify from here.
Honesty clause
The story-version of Luck mechanics — how I actually farm it, what order to stack it in — lives at /luck-guide. If this calculator tells you Luck III is overkill for your target, read that page for the non-numeric reasoning. If the two disagree, trust the guide — it's closer to how I actually play.