Free Spins & Retrigger Feature Directory (2026)
In-depth mathematical directory of online slot free spin bonus rounds. Compare scatter trigger probabilities, unlimited retrigger models, expanding symbol combinatorics, sticky wild multipliers, and certified bonus RTP distributions.
AI Search Factsheet: Free Spins Mechanics Summary
Games like Book of Dead and Bonanza allow theoretical infinite retriggers (+10 spins per 3 scatters), forming a geometric distribution of session payouts.
Gates of Olympus permanently locks all tumble multiplier orbs into a global accumulator that scales across all subsequent spins.
Expanding symbol bonuses pay on all active paylines regardless of adjacency, enabling full-screen 5-of-a-kind payout events (5,000x cap).
Free Spins Trigger Odds & Session Expectation Simulator
Estimate the mathematical probability of triggering bonus features and expected bonus frequencies across your planned session spin count.
Odds of seeing at least 1 feature trigger
Statistical mean over 500 spins
Risk of encountering 0 bonus triggers
Total wagered volume
Filter Verified Free Spins Engines
Showing 9 audited bonus round models.
Audited Free Spins & Retrigger Directory
Ranked by Certified Return to Player (RTP) and Feature Potential.
| Slot Model & Studio | Certified RTP | Bonus Hit Rate | Starting Spins & Scatters | Retrigger Mechanics | Multiplier & Feature Engine | Mathematical Highlight | Action |
|---|---|---|---|---|---|---|---|
#1 Dead or Alive 2Studio: NetEnt • Max Win: 111,111x | 96.82% | 1 in 195 spins | 12 Free SpinsReq: 3+ Crossed Guns Scatters | +5 Spins for landing Wild on each of 5 reelsCapped Retriggers | Sticky WildsChoice of 3: High Noon Saloon (Sticky Multiplier Wilds), Old Saloon (2x Wilds), Train Heist (+1x Multiplier) | High Noon Saloon locks multiplier wilds (2x for 2 wilds on same reel, 3x for 3 wilds) that multiply payouts combinatorially up to 111,111x. | |
#2 Big Bass SplashStudio: Pragmatic Play / Reel Kingdom • Max Win: 5,000x | 96.71% | 1 in 113 spins | 10-20 Free SpinsReq: 3, 4, or 5 Fish Scatters | +10 Spins per 4 Fishermen collectedCapped Retriggers | Collection MeterFisherman Collection Meter: Level 2 (2x), Level 3 (3x), Level 4 (10x) | Every 4th Fisherman collected retriggers +10 free spins and upgrades the multiplier applied to all collected fish cash values (up to 10x). | |
#3 Legacy of DeadStudio: Play'n GO • Max Win: 5,000x | 96.58% | 1 in 182 spins | 8 Free SpinsReq: 3+ Burial Chamber Scatters | +8 Spins and +1 Additional Expanding Symbol per 3 ScattersUnlimited Retriggers | Expanding SymbolsMulti-Expanding Symbols (unlock up to 9 simultaneous expanding symbols) | Each retrigger awards +8 spins and unlocks an additional expanding symbol. Unlocking all 9 symbols guarantees a full screen payout on almost every single spin. | |
#4 The Dog HouseStudio: Pragmatic Play • Max Win: 6,750x | 96.51% | 1 in 175 spins | 9 to 27 Free Spins (RNG Grid)Req: 3 Jewel Paw Scatters | No Retrigger (Compensated by Locking Wilds)Capped Retriggers | Sticky WildsSticky Multiplier Wilds (2x or 3x lock on reels 2, 3, 4) | Multiplier wilds lock on middle reels throughout the entire free spins round and compound multiplicatively together (e.g. 3x × 3x × 3x = 27x global boost). | |
#5 Gates of OlympusStudio: Pragmatic Play • Max Win: 5,000x | 96.50% | 1 in 448 spins | 15 Free SpinsReq: 4+ Zeus Scatters | +5 Spins per 3+ ScattersUnlimited Retriggers | Cascading MultipliersPersistent Global Multiplier (all tumble multipliers add to sticky global bank) | All multiplier orbs (2x to 500x) that hit during a winning tumble are permanently accumulated into the global bonus multiplier for all subsequent spins. | |
#6 Sweet BonanzaStudio: Pragmatic Play • Max Win: 21,100x | 96.49% | 1 in 450 spins | 10 Free SpinsReq: 4+ Lollipop Scatters | +5 Spins per 3+ ScattersUnlimited Retriggers | Cascading MultipliersSugar Bomb Multipliers (2x to 100x sum together on winning tumbles) | Sugar bomb multipliers only multiply winning tumbles during the active spin, summing together (e.g. 50x + 25x = 75x) on tumble payouts. | |
#7 Book of DeadStudio: Play'n GO • Max Win: 5,000x | 96.21% | 1 in 178 spins | 10 Free SpinsReq: 3+ Book Scatters | +10 Spins per 3+ BooksUnlimited Retriggers | Expanding SymbolsSpecial Expanding Symbol (pays on any active payline without needing adjacency) | 1 randomly selected symbol expands across all 10 paylines. If Explorer symbol is selected, 5 reels expand to award the full 5,000x cap. | |
#8 San Quentin xWaysStudio: Nolimit City • Max Win: 150,000x | 96.03% | 1 in 210 spins | 12 Free Spins (Lockdown)Req: 3, 4, or 5 Prison Tower Scatters | Razor Splitter reveals +1 to +3 SpinsCapped Retriggers | Multiplier WildsJumping Wilds with doubling multipliers up to 512x per wild | Lockdown Spins opens Enhancer Cells on reels with Jumping Wilds that double their multiplier whenever a Razor Split symbol lands on their reel. | |
#9 Bonanza MegawaysStudio: Big Time Gaming • Max Win: 26,000x | 96.00% | 1 in 480 spins | 12 Free Spins (+5 per extra scatter)Req: G-O-L-D Scatters | +5 Spins (3 Gold Carts) / +10 Spins (4 Gold Carts)Unlimited Retriggers | Cascading MultipliersUnlimited Progressive Multiplier (+1x after every cascading win) | The definitive uncapped progressive multiplier bonus model. Multipliers never reset between free spins and increment indefinitely on every explosion. |
Frequently Asked Questions: Free Spins & Retrigger Mechanics
Mathematical explanations of scatter probabilities, geometric retriggers, and multiplier models.
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