Universal Tower Defense X: Trait Reroll Calculator
277 pity system probability calculator. See your exact chances of rolling an S-rank trait based on current pity count.
Quick Summary
UTDX uses a 277-roll pity system for S-rank traits. This calculator shows your exact probability of getting Ruler, Eternal, or any S-rank trait based on your current pity count. Input your pity counter to see: chance on next roll, expected rolls remaining, and optimal stop/continue decision points. Stop wasting reroll tokens on bad odds — math tells you exactly when to push and when to wait.
Cumulative Probability Curve
📋 Quick Reference
🔄 How Trait Rerolling Works in UTDX
Every unit in Universal Tower Defense X (UTDX) can equip a trait that modifies its combat stats. Traits come in three tiers: B-rank (common, minor stat bonuses), A-rank (uncommon, moderate multipliers), and S-rank (rare, game-changing abilities). When you perform a trait reroll, the game randomly assigns a new trait to that unit — replacing the old one.
- Ruler — Massive single-unit damage multiplier. Best for carry strategies.
- Eternal — Stacking damage that scales over long fights. Ideal for endurance.
- Fission — AoE damage amplifier. Niche but powerful in splash comps.
UTDX guarantees an S-rank trait after exactly 277 unsuccessful rerolls. Each roll that doesn't yield an S-rank increments your pity counter by 1. At 277, the next roll is a guaranteed S-rank. Pity resets to 0 upon receiving any S-rank trait. You can use Trait Reroll Tickets (obtained from events and battle pass) or spend Gems (100 gems per roll) to reroll.
💡 Tip: Each roll is independent at 0.3%. The pity is a safety net, not a rate increase. Statistically, ~57% of players will get an S-rank within 277 rolls from base rate alone.
💡 Trait Reroll Strategy Tips
Trait reroll tickets are scarce. Only spend them on Mythic-tier units you plan to use long-term. A B-rank carry with an S-rank trait still underperforms a Mythic unit with an A-rank trait.
If you run one hyper-carry, Ruler is your best S-rank. If your comp relies on drawn-out fights with multiple DPS units, Eternal eventually out-damages Ruler after wave 15+.
Farm units like gold generators or XP boosters don't benefit from damage traits. An S-rank trait on a farm unit is essentially deleted value. Always equip damage traits on your actual DPS.
UTDX displays your current pity counter in the trait reroll menu. Check it before spending gems — if you're above 200 pity, it may be worth pushing to 277 for the guaranteed S-rank.
Understanding the UTDX Trait Reroll System
The UTDX trait reroll system is one of the most important progression mechanics in Universal Tower Defense X. Every unit can hold one trait, and the difference between a B-rank trait and an S-rank trait like Ruler or Eternal can mean the difference between clearing and failing endgame content. The 277 pity system ensures that every player eventually receives an S-rank trait — but understanding the underlying probability helps you plan your resources. With a base S-rank trait drop rate of 0.3% per roll, you have roughly a 14% chance of getting one within 50 rolls, a 26% chance within 100 rolls, and a guaranteed drop at 277. This calculator helps you visualize those odds and make informed decisions about when to spend your trait reroll tickets or gems.
Choosing the best trait for your unit depends on your team composition and game mode. For most players pushing tower defense stages, Ruler is the consensus pick — it provides a flat damage multiplier that synergizes with every DPS unit in the game. Eternal is the mathematically superior choice for infinite-scaling modes where fights last beyond wave 20, as its stacking mechanic compounds over time. Fission sees niche use in AoE-heavy compositions. Regardless of which S-rank trait you target, always prioritize rolling on your strongest Mythic carry first. The trait reroll pity counter persists across sessions, so there's no rush — but there's also no reason to waste rolls on units you'll eventually bench. Use this UTDX trait reroll calculator to track your pity progress and calculate exactly how many rolls you need for a comfortable chance at an S-rank trait.
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❓ Frequently Asked Questions
📊 Data Source & Methodology
Unit stats, trait multipliers, and gacha rates sourced from in-game data and developer patch notes. DPS calculations verified against in-game damage testing.
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