Codex of Dusk: a free Book of Dead alternative
Built like Book of Dead: five reels, ten lines, one symbol that is both wild and scatter, free spins with a special symbol that expands, and a card gamble on any win. Played with chips that are worth nothing, with the machine's real numbers and a session coach beside it.
The codex is wild. 3 or more anywhere start 10 free spins with an expanding special symbol.
Play chips
1,000
A spin costs 10
Win
0
Lines
10
Line bet
1
Pick your lines and a bet per line, then spin.
10 lines at 1 a line. No real money, no prizes, nothing to buy.
Session coach
Last round
Nothing played yet. After each of your spins the coach says what the round cost and what decided it.
Decide the cost before you start
Gambling is entertainment with a price, like a concert ticket. The useful question is not how much you might win but how much the evening is allowed to cost. Pick that number first, and treat reaching it as the end of the session. You can set one below and the coach will hold you to it.
Next bet
10 chips at a 4.15% house edge: an expected cost of 0.4 chips.
- Spins played
- 0
- Chips bet in total
- 0
- Bets raised after a loss
- 0
Where the result came from
- House edge, on average
- 0
- Luck
- 0
- Result
- 0
The report fills in as you play. See how often a slot bankroll busts
Set a session limit
This table is for practice and entertainment only. How to keep gambling safe
What the lines pay
| Symbol | 2 | 3 | 4 | 5 |
|---|---|---|---|---|
| Archivist | 12 | 80 | 800 | 4,000 |
| Astrolabe | 8 | 35 | 300 | 1,500 |
| Lamp | 6 | 30 | 100 | 600 |
| Urn | 6 | 30 | 100 | 600 |
| Star | 5 | 30 | 100 | |
| Crescent | 5 | 30 | 100 | |
| Wave | 4 | 15 | 60 | |
| Palm | 4 | 15 | 60 | |
| Spiral | 4 | 15 | 60 | |
| Codex, anywhere | 30 | 150 | 1,500 |
Chips paid at 10 lines and 1 a line. Lines pay from the left reel. The dimmer figures are payouts smaller than the whole bet: a single line of those costs more than it returns. The codex stands in for every symbol on a line, and 3 or more anywhere pay the amounts in the last row and start 10 free spins. In the free spins one symbol, drawn at random, expands to fill every reel it lands on and then pays on every line in play, whichever reels those are. The most a round can pay is 5,000 times the bet.
The lines (10 of 10 in play)
- 1Line 1, in play: middle, middle, middle, middle, middle
- 2Line 2, in play: top, top, top, top, top
- 3Line 3, in play: bottom, bottom, bottom, bottom, bottom
- 4Line 4, in play: top, middle, bottom, middle, top
- 5Line 5, in play: bottom, middle, top, middle, bottom
- 6Line 6, in play: middle, top, top, top, middle
- 7Line 7, in play: middle, bottom, bottom, bottom, middle
- 8Line 8, in play: top, top, middle, bottom, bottom
- 9Line 9, in play: bottom, bottom, middle, top, top
- 10Line 10, in play: middle, top, middle, bottom, middle
What this machine costs
- Return to player
- 95.85%
- The machine keeps 4.15%
- Expected cost of a spin
- −0.41
- At a bet of 10
- Spins that pay anything
- 27.0%
- 18.3% pay less than the bet
- Spins that gain chips
- 8.5%
- Free spins on 1 spin in 116
- Return from the free spins
- 51%
- Share of everything paid back
- Half of features add under
- 35× bet
- The average is 56× the bet
The hit rates are for 10 lines and are counted from the reel strips: every one of the 24,564,384 ways the reels can stop. The return and the feature figures are simulated over 10,000,000 features, and the return is the same on any number of lines. None of it includes the gamble, which is an even bet and changes the swings, not the return. See what a return like this does to a bankroll over a session
This session
- Spins
- 0
- Chips staked
- 0
- Net chips
- 0
- Expected at this return
- 0
- Spins that paid
- 0
- Paid less than the bet
- 0
A round counts for what it was worth once any gamble was over, so a win gambled away counts as a spin that paid nothing. The machine lights up for every paying spin. The last figure is how many of those left you with fewer chips than before.
Built by Alexander Korsager · last updated October 3, 2026 · corrections
- Of the chips bet, paid back over the long run
- 95.85%
- Of that return, the share that comes from the free spins
- 51%
- Of the spins that pay, the share that pay less than they cost
- 68%
- Chance of 100 spins without the free spins once
- 42%
01 / 03
A book slot with its numbers on show
Codex of Dusk is a free Book of Dead alternative: our own slot machine, built to play the way Play'n GO's Book of Dead plays.
Five reels, three rows and 10 lines that pay from the left. One symbol, the codex, is both the wild and the scatter, and 3 or more of them anywhere start 10 free spins. Before those spins, the codex opens and picks one symbol at random, and for the rest of the feature that symbol expands to fill every reel it lands on and pays across the lines even when those reels are not next to each other. Any win can be collected or staked on the turn of a card. If you came looking for a free game like Book of Dead, this is that mechanic. The name, the art, the sound, the reel strips and the pay table are ours.
As the reels stop
After it expands
30xthe bet: 3 of a kind pays 30 times the line bet, on all 10 lines
The 3 reels are not next to each other and the expanded symbol pays anyway. The lines on this screen pay nothing on their own.
What is different from Book of Dead, and from any real machine, is everything a real machine leaves out.
This one returns 95.85% of the chips bet on it and keeps 4.15%. About half of that return, 51% of it, comes from the free spins, which start on about 1 spin in 116. In between, 27.0% of spins on all 10 lines pay something, and 68% of those pay less than the spin cost, so only 8.5% of spins leave you with more chips than before. The machine lights up for all of them. The status line under the reels and the coach beside them tell you which kind you just had.
- Paid back by the paid spins
- 47.1%
- Paid back by the free spins
- 48.7%
- Kept by the machine
- 4.15%
The free spins start on about 1 spin in 116. In between, 27.0% of spins pay something and 68% of those pay less than the spin cost.
There is no decision in a slot to get better at, and the gamble is a coin toss, not a skill.
What this page is for is entertainment, and seeing clearly what this kind of machine does: how long it can run without its feature, how it dresses up a small payout, how a gamble turns a win into nothing, and what a session of it costs on average.
- Call the color26 in 52
Pays 2 times the win. On average a call returns 1 times what was staked.
- Call the suit13 in 52
Pays 4 times the win. On average a call returns 1 times what was staked.
- The color, right 5 times running1 in 32
The other 31 times the whole win is lost.
Each bar is the chance the call wins. A wrong call loses the whole win, so the gamble widens the swing and leaves the return where it was.
02 / 03
Rules at this table
| Symbol | Five in a row | Three in a row |
|---|---|---|
| Archivist | 4,000x | 80x |
| Astrolabe | 1,500x | 35x |
| Lamp | 600x | 30x |
| Urn | 600x | 30x |
| Star | 100x | 5x |
| Crescent | 100x | 5x |
| Wave | 60x | 4x |
| Palm | 60x | 4x |
| Spiral | 60x | 4x |
A spin on all 10 lines costs 10 line bets, so three Spirals on one line pay back 4 of the 10: a payout smaller than the spin cost, which is a loss.
- Five reels, three rows and up to 10 lines. You choose how many lines to play, from 1 to 10, and a bet per line of 1, 2, 5 or 10 chips. A spin costs the line bet times the lines in play.
- A line pays for matching symbols in a row counted from the left reel. The 4 premium symbols (Archivist, Astrolabe, Lamp, Urn) pay for two or more in a row. The 5 glyphs pay for three or more.
- Archivist is the highest symbol: five on a line pay 4,000 times the line bet. The lowest glyphs pay 4 times the line bet for three, which on all 10 lines at a line bet of 1 is 4 chips back on a 10 chip spin.
- The codex is wild: it stands in for every paying symbol on a line. It is also the scatter: 3, 4 or 5 codexes anywhere in view pay 3, 15 or 150 times the whole bet.
- 3 or more codexes anywhere award 10 free spins, played at the bet and lines of the spin that started them. Before they begin, one of the 9 paying symbols is drawn at random as the special symbol for the whole feature.
- On a free spin the lines are paid first, as usual. Then, if the special symbol is in view on enough reels to make a win (two reels for a premium, three for a glyph), it expands to cover each of those reels and pays that many of a kind on every line in play, wherever the reels sit. The codex does not stand in for the special symbol when it expands.
- 3 or more codexes during the free spins award 10 more, with the same special symbol. There is no limit on how many times that can happen.
- The most one round can pay is 5,000 times the bet. A feature that reaches that amount ends there.
- After any round that paid, the win waits to be collected. You can collect it, or gamble it on a face-down card drawn from a full deck of 52: call the color right and the win doubles, call the suit right and it is multiplied by four, call it wrong and the whole win is lost.
- A correct call can be gambled again, up to 5 correct calls in a row, after which the win is collected for you. A call is only offered while winning it would keep the amount at or under 2,500 times the bet. Pressing Spin collects a waiting win first.
- Autoplay plays 10, 25, 50 or 100 spins at the current lines and line bet. It needs a loss limit before it starts, and it stops at that limit, when the spins run out, when you stop it, or once a round of free spins has played. While it runs, each win is collected automatically and no gamble is offered, and the lines and the line bet cannot be changed.
- The whole round, free spins included, is decided when Spin is pressed. The animation plays it back and cannot change it. Each gamble card is drawn when you make the call.
Sound starts on, and the Sound button switches it off.
- Enter
- Spin, or collect a waiting win first
FAQ
- Is this slot played for real money?
- No. The table uses play chips that have no value, cannot be bought, and cannot be cashed out or exchanged for anything. If you run out, you are handed another stack for free. There is no account and nothing to download.
- What is the RTP of Codex of Dusk?
- 95.85%, so the machine keeps 4.15%. The paid spins on their own return 47.1% and that part is counted exactly from the reel strips. The free spins add 48.7%, and that part is simulated over 10,000,000 features, which puts the total within about 0.03 of a percentage point either way. On all 10 lines at the smallest line bet that works out at about 41 chips per 100 spins on average, with very wide swings around it in any one session.
- How often does it pay, and how often do the free spins start?
- On all 10 lines, 27.0% of spins pay something, about 1 in 4. But 18.3% of spins pay less than the bet, which is a net loss that looks like a win. Only 8.5% of spins, about 1 in 12, pay more than they cost. The free spins start on about 1 spin in 116, so there is a 42% chance of playing 100 spins without seeing them once.
- Is Codex of Dusk a free alternative to Book of Dead?
- Yes. It is built like Book of Dead: five reels, three rows, 10 lines paying from the left, one symbol that is both wild and scatter, 10 free spins for 3 or more of them, a special symbol picked at random that expands during the free spins, and a card gamble on a win. It is free, it needs no account, and it is played with chips that have no value. It is not Book of Dead itself, which is Play'n GO's game, and it is not made, licensed or endorsed by Play'n GO.
- How is it different from Book of Dead?
- The mechanic is the same family and everything else is our own: the name, the art, the sound, the reel strips and the pay table. So the numbers are different too. Codex of Dusk returns 95.85% with a 27.0% hit rate, and those are this machine's figures only. They say nothing about Book of Dead's. The other difference is what sits beside the reels: the published figures, a status line that calls a payout smaller than the bet a loss, and a session coach.
- Does the gamble feature change the return?
- No. The card is drawn from a full deck of 52, so a color call wins 26 times in 52 and pays double: 26/52 times 2 is exactly 1. A suit call wins 13 times in 52 and pays four times: 13/52 times 4 is also exactly 1. On average a call returns what was staked, so the gamble neither adds to the 95.85% nor takes from it, and that figure is for the machine without gambling. What the gamble does change is the swing. Every call puts the whole win at risk, and calling the color right 5 times in a row happens 1 time in 32. A 40 chip win gambled that far is 1,280 chips 1 time in 32 and nothing the other 31 times.
- Does autoplay change the odds?
- No. Every spin is drawn the same way and the return stays 95.85%. What autoplay changes is speed: more spins fit into an hour, and the cost of an hour is the number of spins times the 4.15% the machine keeps on each. That is why autoplay here will not start without a loss limit, and why it stops after a round of free spins so that a feature is never played past unseen.
- Does playing fewer lines change anything?
- It does not change the return: every line has the same chance of every result, and the scatter and the expanding symbol pay in proportion to the lines in play, so the machine returns the same share of the bet on 1 line as on 10. That part is counted, not estimated. What changes is how the return arrives. On 1 line only 4.2% of spins pay anything, against 27.0% on 10, so the gaps are longer and the swings relative to the bet are larger.
- Can I tell when the free spins are coming?
- No. Each reel stops on its own, every stop on a strip is equally likely, and a spin starts from nothing. A run of blank spins does not make a feature due. Two codexes landing with no third is not a sign of anything: it pays exactly what any other losing spin pays, and the next spin has the same chance of free spins as the last one.
- What is the most a spin can pay?
- 5,000 times the bet. That is a cap the machine enforces: a round that reaches it stops there. In the simulation 25 of 10,000,000 features reached it. A round that pays 100 times the bet or more comes up about once in 691 spins. Half of all features add less than 35 times the bet.
How this game works
Each reel is a fixed strip of symbols, 36, 36, 26, 27, 27 symbols long from reel 1 to reel 5. A spin picks one stop on each strip with your browser's random number generator, every stop equally likely, and the three symbols from that stop down are what shows. The free spins use the same strips. There are 24,564,384 ways the five reels can stop on one spin.
Part of this machine is counted and part is simulated, and the two are kept apart. Counted exactly, from every one of those combinations: what a paid spin pays and how often, how often it starts the free spins, and what a single free spin pays under each of the 9 possible special symbols. So the hit rate, the 18.3% of spins that pay less than the bet, the 1 in 116 feature rate and the 47.1% the paid spins return are exact. The house edge on the common casino bets puts the 4.15% this machine keeps in context.
Simulated: how a feature adds up. A feature is 10 free spins that can retrigger without limit and stop at the cap, and that chaining is run 10,000,000 times with a seeded generator (seed 20261003), drawing each free spin from its counted distribution. The 48.7% the feature adds, the 95.85% total, the standard deviation and the odds of a large win come from that run. One standard error on the return is 0.03 of a percentage point. An automated test re-runs the count and the whole simulation from the same seed and requires them to reproduce the published figures, and checks the simulation against the machine's own engine.
From those: a feature's free spins add 56.3 times the bet on average, but half of them add less than 35 times and 10% add less than 10 times. A feature runs 10.9 free spins on average. The spread of one spin's result has a standard deviation of 12.8 bets, which is high: most of the time the machine pays back well under its average, and now and then far over it.
The gamble is not in any of those figures. A color call wins on 26 cards in 52 and pays double, a suit call wins on 13 in 52 and pays four times, so each returns exactly what is staked on average. The return is the same with or without it. The spread is not: the gamble makes it wider.
The expected figure in the session panel is the share the machine keeps multiplied by the chips you have bet on finished spins. The coach's count of spins in the last minute is taken from when you pressed Spin.
Limits
- The reel strips and pay table were designed for this page. They are not a copy of Book of Dead or of any other real machine, and these figures describe this machine only.
- Book of Dead is Play'n GO's game and its name belongs to its owner. Codex of Dusk is an independent alternative built on the same kind of mechanic. It is not made, licensed or endorsed by Play'n GO.
- The return, the deviation and the large-win odds rest on a simulation and carry its sampling error, stated above. The hit rates and the feature rate do not: they are counted.
- A real slot is usually shipped in several return settings and the casino chooses one. The same title can keep noticeably more than the figure quoted for it, and a real machine does not print its reel strips.
- The reels and the gamble card are drawn by an ordinary browser random number generator. It is not an audited or certified generator, and nothing here should be read as a test of one.
- Autoplay is here because the machine this one is modeled on has it. It makes a machine cost more per hour, so it will not start without a loss limit, and the coach prices the pace while it runs. There is no turbo mode, because the sources we checked do not show that the original has one, and no bonus buy.
- Play chips do not feel like money. A long run without the feature is harder to sit through, and a gamble is harder to walk away from, with a real stake.
This is a practice game for adults. It has no real-money play and links to none. Book of Dead, or any slot played with money, keeps its share of every spin, and no way of timing the spins, choosing the lines or gambling the wins changes that. On this machine 68% of the spins that pay anything still cost more than they return, and about half of the return sits in a feature that 100 spins miss 42% of the time.
Gambling can cause serious harm. The National Problem Gambling Helpline is free, confidential and open 24/7, call or text 1-800-MY-RESET (1-800-697-3738), or chat at ncpgambling.org/chat.
03 / 03
Go deeper
- Slot RTP and volatility simulator What a return and a volatility level do to a bankroll over hundreds of spins.
- Variance simulator Why two sessions at the same expected cost can end in very different places.
More slots
See all- Prism WildsA free Starburst alternative: expanding wilds and respins, with its return and hit rate counted and shown.
- Lotus ThroneA free Cleopatra alternative: 20 lines, a doubling wild and 15 tripled free spins, with the return counted and shown.
- Nightfall ManorA free Blood Suckers alternative: 25 lines, tripled free spins and a coffin pick bonus, at a counted 98% return.
- Tidal HaulA free Big Bass Bonanza alternative: free spins where a collector takes every fish value in view, with the math shown.