Last updated: May 2026. Both games tested across April-May 2026 at the four featured AU casinos plus standalone Novomatic-licensed venues for Book of Ra Deluxe verification.
The book-slot genre starts and ends with two names. Book of Ra Deluxe by Novomatic — the original, the temple-and-pharaoh slot that defined the category in the mid-2000s and remains the most-played pokie at land-based venues across continental Europe. And Book of 99 by Relax Gaming — the 2021 entrant that reused the genre's blueprint but stapled a 99% RTP onto it. They're cousins on the surface: 5-reel grids, 10 paylines, a single expanding symbol in free spins, book-as-scatter-and-wild. Underneath, the math is wildly different. This article compares them head-to-head so you can decide which one fits your session.
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At-a-glance comparison
| Spec | Book of 99 (Relax) | Book of Ra Deluxe (Novomatic) |
|---|---|---|
| Released | 4 May 2021 | 2008 (Deluxe upgrade) |
| Theme | Greek mythology (Orpheus) | Egyptian (explorer + Ra) |
| Grid | 5 × 3 | 5 × 3 |
| Paylines | 10 fixed | 10 (5 in original) |
| RTP | 99% | 95.1% |
| Volatility | High | Medium-High |
| Max win | 12,075× stake | ~5,000× stake |
| Free spins | 10 (one expanding symbol) | 10 (one expanding symbol) |
| Retrigger | ✅ Yes (3+ books = +10) | ✅ Yes |
| Bonus Buy | ✅ Yes (AU casinos) | ❌ No (Novomatic doesn't offer it) |
| Demo available | ✅ Yes | ✅ Yes |
| Mobile (HTML5) | ✅ Yes | ✅ Yes |
| AU casino availability | All 4 featured | Available but less common |
The RTP gap — the headline difference
Book of 99: 99% RTP vs Book of Ra Deluxe: 95.1% RTP.
That's a 3.9 percentage point gap. On a A$100 spin budget, the expected return is:
| Game | Expected return per A$100 spun |
|---|---|
| Book of 99 | A$99 |
| Book of Ra Deluxe | A$95.10 |
A A$3.90 difference per A$100 doesn't sound like much in isolation. Across a 5,000-spin session at A$1 stakes, the gap is A$195. Across a year of weekly sessions for a regular player, it's hundreds of dollars retained.
Verdict: Book of 99 wins decisively on RTP. This is the single biggest reason to pick it over Book of Ra Deluxe. The 99% RTP math is explained in depth here.
The max-win gap
Book of 99: 12,075× stake. From a A$1 stake, A$12,075.
Book of Ra Deluxe: ~5,000× stake (variants exist). From a A$1 stake, ~A$5,000.
Book of 99 offers more than double the max-win ceiling. The path is similar — Orpheus (Book of 99) or the explorer (Book of Ra) as the expanding symbol, landing on multiple reels in free spins. Same mechanic, different cap.
Verdict: Book of 99 wins on max-win headroom. Especially relevant for max-bet chasers.
Volatility — same shape, slightly different feel
Both games are book-genre, which means high variance with rare-but-rewarding free-spin rounds.
Book of 99 is officially rated high volatility — Relax explicitly tuned the base game's hit frequency down to fund the bonus payouts. Dry stretches of 100+ spins are common.
Book of Ra Deluxe is medium-high volatility — slightly higher base-game hit frequency (you'll see more small wins between bonuses) but lower bonus-round ceilings because the math wasn't tuned as aggressively toward big payouts.
Verdict: if you prefer higher highs and lower lows, Book of 99. If you prefer a smoother session with smaller bonus payouts, Book of Ra Deluxe.
Themes and visuals
Book of 99 — Greek mythology. Orpheus the lyre-poet, marble columns, scrolling parchment, moody temple soundtrack. Modern Relax Gaming visual style — clean, atmospheric, well-animated. Released 2021, looks 2021.
Book of Ra Deluxe — Ancient Egypt. An Indiana Jones-style explorer, hieroglyphs, the eye of Ra, pyramids in the background. The Deluxe upgrade gave it a polish over the 2005 original but it still looks 2008. Iconic but dated.
Verdict: subjective. Aussies raised on Book of Ra at the local pub will feel nostalgia for the Egyptian theme. New players coming to book slots fresh in 2026 tend to prefer Book of 99's cleaner visual.
Bonus Buy availability
Book of 99 — Bonus Buy enabled at all four featured AU casinos. Roughly 100× stake to trigger free spins directly.
Book of Ra Deluxe — No Bonus Buy. Novomatic is one of the last major studios that refuses to add Bonus Buy to its book slots, on the grounds that it cheapens the natural trigger anticipation. You play Book of Ra Deluxe with the natural trigger or not at all.
Verdict: Book of 99 wins for streamers and time-constrained players who want Bonus Buy. Book of Ra Deluxe wins for purists who want the natural-trigger experience.
Mobile play
Both games run HTML5 in any modern mobile browser. Both have:
- 60fps animations on flagship phones
- Portrait and landscape modes
- Touch-friendly UI
- Identical math to desktop
Book of 99's visual scales better to small screens — the Relax Gaming UI was designed mobile-first.
Book of Ra Deluxe was originally designed for land-based cabinets and the mobile port is functional but slightly cramped on smaller phones.
Verdict: Book of 99 wins on mobile UX, particularly on iPhone SE and similar smaller phones.
Availability at Australian casinos
| Casino | Book of 99 | Book of Ra Deluxe |
|---|---|---|
| Vegasnova | ✅ Yes | ✅ Yes |
| Joe Fortune | ✅ Yes | ✅ Yes |
| GreatSlots | ✅ Yes | ❌ No (Novomatic catalogue not fully stocked) |
| CasinoRocket | ✅ Yes | ✅ Yes |
Book of 99 is more reliably stocked because Relax Gaming distributes through a larger network of B2B aggregators. Novomatic has more restrictive licensing and not every offshore casino carries the full Greentube/Novomatic library.
Verdict: Book of 99 wins on availability. Easier to find at AU-targeting casinos.
Welcome-bonus wagering contribution
Most casinos have specific rules about which games contribute to welcome-bonus wagering. Common patterns:
Book of 99 — typically contributes 100% to wagering at most casinos, BUT some casinos explicitly exclude or reduce contribution for high-RTP games to prevent advantage-play exploitation. Verify in the bonus terms at your casino.
Book of Ra Deluxe — usually 100% wagering contribution with no special restrictions. Lower RTP means casinos don't worry about advantage-play exploitation.
Verdict: for wagering bonus clearing, Book of Ra Deluxe is often the safer choice because there are fewer terms-gotchas. Book of 99 is better if you're already on the casino's clean money (not bonus funds).
Studio and licensing
Relax Gaming — Malta-headquartered, MGA-licensed B2B studio. Founded 2010. Known for clean math, modern UI, and high-RTP showcase titles. Their game catalogue extends from Book of 99 through Money Train (one of the highest-variance slot lines in the industry) to live-game integrations.
Novomatic — Austrian gambling-tech conglomerate, the parent of Greentube (the digital arm). Founded 1980. The pioneer of book slots; Book of Ra defined the genre. Operates land-based cabinets across hundreds of European venues plus online distribution.
Verdict: both reputable, both well-licensed. Different focus — Relax is modern online-first; Novomatic is land-based-first with online as an extension.
Which should you play?
Use this matrix:
| If you want… | Pick |
|---|---|
| Highest mathematical edge | Book of 99 |
| Maximum potential win | Book of 99 |
| Bonus Buy to skip the grind | Book of 99 |
| Best mobile UX | Book of 99 |
| Greek mythology theme | Book of 99 |
| Egyptian theme / nostalgia for the classic | Book of Ra Deluxe |
| Smoother base-game variance | Book of Ra Deluxe |
| Welcome-bonus wagering clear (no high-RTP exclusion risk) | Book of Ra Deluxe |
| The original book slot | Book of Ra Deluxe |
Default recommendation for AU players in 2026: Book of 99, primarily because of the RTP advantage. Book of Ra Deluxe remains worth playing for the nostalgia and for wagering-clearance scenarios — but on pure math, Book of 99 is the cleaner choice.
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Quick FAQ
Is Book of 99 a Book of Ra ripoff? No — same genre (book slots with expanding symbols), but Relax Gaming designed the math, theme, and visuals independently. Genre conventions aren't copyright.
Why doesn't Novomatic just make a 99% Book of Ra? Commercial decision. A 4-5% house edge generates four-to-five times the revenue of a 1% house edge. Novomatic's books are revenue-driving titles for them; they have no incentive to undercut their own margin.
Are there other 99% book slots? Not from Tier-1 studios at the time of writing. Relax Gaming is the only major studio that's released a 99% RTP mainstream slot — we compare it to every 99%+ alternative (Mega Joker, Ugga Bugga, Jackpot 6000).
Can I play both at the same casino? Yes at three of the four featured casinos (excluding GreatSlots which doesn't stock the full Novomatic catalogue).
Which has the better-looking expanding symbol animation? Subjective. Book of 99's Orpheus expanding is visually richer (full-reel parchment unfurl); Book of Ra Deluxe's explorer expansion is iconic and instantly recognisable.
Do they share the same RNG? No — different studios, different RNG implementations. Both certified independently.
Should I play Book of Ra Magic / 6 / Mystic Fortunes instead? Those are Novomatic's higher-variance sequels to Book of Ra. They sit at similar 95-96% RTP. Book of 99 still wins on RTP.
About this comparison
Both games tested across April-May 2026. Book of 99 at our four featured AU casinos. Book of Ra Deluxe at Vegasnova, Joe Fortune, and CasinoRocket. Test spins: 200+ per game.
Gambling responsibly. Comparing slots is useful; pretending the comparison gives you an edge isn't. Both games are high-variance entertainment, not income. Set deposit limits before you start. AU support: gamblinghelponline.org.au · BetStop · 18+ only.
Further Reading
Related reading in this guide: