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Caldera Cash: a free Cash Eruption alternative

Built like Cash Eruption: five reels, twenty lines, prize symbols that lock for a hold and respin, four prize tiers and free spins on linked reels. Played with chips that are worth nothing, with the machine's real numbers and a session coach beside it.

Grand
20,000
Major
2,000
Minor
1,000
Mini
400

6 or more Embers start the hold and respin. 3 or more Calderas award 6 free spins.

Play chips

2,000

Bet

20

Win

0

Pick a bet and spin. All twenty lines play on every spin.

20 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

20 chips at a 3.57% house edge: an expected cost of 0.7 chips.

This table is for practice and entertainment only. How to keep gambling safe

What the lines pay

What three, four and five of each symbol pay in chips at a bet of 20
Symbol345
Obsidian Idol3075300
Fire Opal2040150
Drum1525100
Flame Stone102060
Wave Stone51040
Leaf Stone51040
Caldera, anywhere1003001,200

Chips paid at a bet of 20. A line pays from its left end only, once, for its longest run. The dimmer figures are payouts smaller than the bet: a single line of those costs more than it returns. The wild lands on reels 2 to 5, stands in for every paying symbol, and fills its reel when that reel is part of a win. Idols filling reel 1 with a wild on each other reel is the Idol Wall, which pays 10,000 in place of the lines. Three or more Calderas also award 6 free spins.

What an Ember carries

The prize an Ember can carry at a bet of 20 and how often it carries it
PrizeChipsShare of Embers
1 × bet2043.0%
2 × bet4026.0%
3 × bet6013.0%
5 × bet1008.0%
10 × bet2005.0%
Mini4003.0%
Minor1,0001.5%
Major2,0000.5%
Grand, for a full board20,0001 feature in 5,154

An Ember pays nothing until 6 or more are in view. Then they lock, every other position respins on its own, and each empty position has a 3.5% chance of landing an Ember on each respin. The Grand is 20,000 chips at every bet, so it is 1,000 times a bet of 20. No round pays more than 2,500 times its bet.

The twenty lines

  1. 1Line 1: middle, middle, middle, middle, middle
  2. 2Line 2: top, top, top, top, top
  3. 3Line 3: bottom, bottom, bottom, bottom, bottom
  4. 4Line 4: top, middle, bottom, middle, top
  5. 5Line 5: bottom, middle, top, middle, bottom
  6. 6Line 6: top, top, middle, top, top
  7. 7Line 7: bottom, bottom, middle, bottom, bottom
  8. 8Line 8: middle, top, top, top, middle
  9. 9Line 9: middle, bottom, bottom, bottom, middle
  10. 10Line 10: middle, top, middle, bottom, middle
  11. 11Line 11: middle, bottom, middle, top, middle
  12. 12Line 12: top, middle, top, middle, top
  13. 13Line 13: bottom, middle, bottom, middle, bottom
  14. 14Line 14: middle, middle, top, middle, middle
  15. 15Line 15: middle, middle, bottom, middle, middle
  16. 16Line 16: top, middle, middle, middle, top
  17. 17Line 17: bottom, middle, middle, middle, bottom
  18. 18Line 18: top, top, bottom, top, top
  19. 19Line 19: bottom, bottom, top, bottom, bottom
  20. 20Line 20: top, bottom, top, bottom, top

What this machine costs

Return to player
96.43%
At a bet of 20. It keeps 3.57%
Expected cost of a spin
−0.71
At a bet of 20
Spins that pay anything
27.2%
10.3% pay less than the bet
Spins that gain chips
13.1%
Standard deviation 5.4 bets
Hold and respin
1 in 119
28% of the return
Free spins
1 in 346
12% of the return

Counted, not estimated: every one of the 161,168,128 ways the reels can stop, the feature solved exactly, and the free spins that follow. The return is a little lower at a larger bet because the Grand stays at 20,000 chips. See what a return like this does to a bankroll over a session

The hold and respin, in odds

Average feature
31.4 bets
44% pay under 20 bets
Embers on the board at the end
7.6
of 15, on average
A Mini in a feature
1 in 4.8
1 paid spin in 569
A Minor in a feature
1 in 9.2
1 paid spin in 1,082
A Major in a feature
1 in 27
1 paid spin in 3,135
A full board, the Grand
1 in 5,154
1 paid spin in 523,407

Per feature started by a paid spin, and per paid spin with any free spins counted in. Five Embers in view, one short, turns up on 1.6% of spins and pays nothing.

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

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 at the smallest bet
96.43%
Of the spins that pay, the share that pay less than they cost
38%
Of the return, the share paid by the hold and respin
28%
Of the Embers that lock, the share carrying 1, 2 or 3 times the bet
82%

01 / 03

A hold and respin, counted position by position

Caldera Cash is a free Cash Eruption alternative: our own slot machine, built to play the way IGT's Cash Eruption plays.

Five reels, three rows and 20 lines that pay from the left, a wild that expands, and prize symbols that each carry a value. Land 6 or more of them and they lock while every other position respins, with 3 respins that reset each time a new one lands. If you came looking for a free game like Cash Eruption, this is that mechanic, with reels that spin and stop, a board that cools to rock for the feature and a counter that flashes back to 3. The name, the island, the symbols, the sound, the reel strips and the pay table are ours.

6 Embers lock, 9 positions respin
the bet, locked so far, if nothing else lands
10x
respins on the counter, and it goes back there each time an Ember lands
3

Each open position has a 3.5% chance of landing an Ember on each respin. The average feature ends with 7.6 of the 15 positions filled.

What is different from Cash Eruption, and from any real machine, is everything a real machine leaves out.

This one returns 96.43% of the chips bet on it at the smallest bet and keeps 3.57%, and that figure is counted from reel strips and weights that are printed in the code this page runs. 27.2% of spins pay something, and 38% of those pay less than the spin cost, so only 13.1% of spins leave you with more chips than before. The hold and respin starts on about 1 spin in 119 and fills the whole board, the only way to the Grand, about once in 523,407 spins. The machine lights up for all of it. The status line under the reels and the coach beside them tell you what each spin did to your stack.

What the reels do, at the smallest bet
of spins pay something
27.2%
of those pay less than the spin cost: a loss
38%
spins start the hold and respin
1 in 119
spins fill the whole board, the only way to the Grand
1 in 523,407

There is no decision in a slot to get better at.

What this page is for is entertainment, and seeing clearly what this kind of machine does: how a counter that resets feels like progress, how small most of the locked prizes are, how rarely a board fills, and what a session of it costs on average.

What one Ember carries, and how often
  • 1 time the bet43.0%
  • 2 times the bet26.0%
  • 3 times the bet13.0%
  • 5 times the bet8.0%
  • 10 times the bet5.0%
  • Mini: 20 times the bet3.0%
  • Minor: 50 times the bet1.5%
  • Major: 100 times the bet0.5%

82% of Embers carry 3 times the bet or less. The average feature pays 31 bets, and 44% of features pay less than 20.

02 / 03

Rules at this table

The four prize tiers, per hold and respin
TierPaysFeatures that show it
Grand: all 15 positions filled20,000 chips1 in 5,154
Major: one Ember carrying it100x the bet1 in 27
Minor: one Ember carrying it50x the bet1 in 9.2
Mini: one Ember carrying it20x the bet1 in 4.8

The Grand is the same 20,000 chips at every bet, so it is 1,000 times the smallest bet and a smaller multiple of a larger one. The other three are fixed multiples. None of them grows.

  • Five reels, three rows and 20 fixed lines. Every spin plays all 20 lines at a bet of 20, 40, 100 or 200 chips, which is one twentieth of that on each line.
  • A line pays for three, four or five of the same symbol in a row, counted from reel 1. Each line pays once, for its longest run.
  • There are six paying symbols. Obsidian Idol is the highest: five on a line pays 300 times the line bet. Leaf Stone is the lowest: three on a line pays 5 times the line bet, which at a bet of 20 is 5 chips back on a 20 chip spin.
  • The wild appears on reels 2 to 5 and stands in for every paying symbol. When its reel is part of a winning line, the wild expands to cover the whole reel.
  • Idols filling reel 1 with a wild on each of reels 2 to 5 is the Idol Wall. It pays 500 times the bet in place of the line wins.
  • Three, four or five Calderas anywhere in view pay 5, 15 or 60 times the bet and award 6 free spins.
  • Every Ember carries a prize: 1, 2, 3, 5 or 10 times the bet, or one of the tiers Mini (20 times the bet), Minor (50) and Major (100). Embers pay nothing unless 6 or more are in view.
  • 6 or more Embers start the hold and respin. They lock, every other position respins on its own, and you have 3 respins. Each new Ember locks and puts the count back to 3. Each empty position has a 3.5% chance of landing an Ember on each respin.
  • The feature ends when the respins run out or all 15 positions are full. Every locked prize is paid, and a full board adds the Grand, which is 20,000 chips at every bet.
  • On a free spin reels 2, 3 and 4 turn as one and show a single giant symbol. A giant Caldera adds 3 spins, to at most 15. A giant Ember locks 9 positions under one prize (5, 8, 12, 15, 25 or 40 times the bet, or a tier) and starts the hold and respin on the other 6.
  • No round pays more than 2,500 times its bet. At the smallest bet that is exactly the Grand plus a board of 15 Majors.
  • Autoplay plays 10, 25, 50 or 100 spins at the current bet. It needs a loss limit before it starts, and it stops at that limit, when the spins run out, or when you stop it. An expanding wild plays through. A hold and respin or free spins play out in full, and then the run stops.
  • The whole round is decided when Spin is pressed. The animation plays it back and cannot change it.

  • Sound starts on, and the Sound button switches it off.

    Enter
    Spin

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 Caldera Cash?
96.43% at the smallest bet of 20 chips, falling to 96.26% at the largest bet of 200. It moves because the Grand is a fixed 20,000 chips, so it is 1,000 times the smallest bet and only 100 times the largest. Both figures are counted from the reel strips and weights, not sampled. At the smallest bet the machine keeps 3.57%, about 71 chips per 100 spins on average, with wide swings around it in any one session.
How often does it pay?
27.2% of spins pay something, about 1 in 4. But 10.3% of spins pay less than the bet, which is a net loss that looks like a win. Only 13.1% of spins, about 1 in 8, pay more than they cost. The hold and respin starts on about 1 spin in 119 and the free spins on about 1 in 346.
Is Caldera Cash a free alternative to Cash Eruption?
Yes. It is built like Cash Eruption: five reels, three rows, 20 lines, an expanding wild, and prize symbols that start a hold and respin when 6 or more land, with 3 respins that reset and four prize tiers. It is free, it needs no account, and it is played with chips that have no value. It is not Cash Eruption itself, which is IGT's game, and it is not made, licensed or endorsed by IGT.
How is it different from Cash Eruption?
The mechanic is the same family and everything else is our own: the name, the volcanic island, the symbols, the sound, the reel strips, the prize values and the pay table. So the numbers are different too. Caldera Cash returns 96.43% with a 27.2% hit rate, and those are this machine's figures only. They say nothing about Cash Eruption's. The other difference is what sits beside the reels: the exact figures, the odds of each prize tier, a status line that calls a payout smaller than the bet a loss, and a session coach.
What are the odds of the Grand and the other tiers?
The Grand needs all 15 positions filled. That happens in about 1 hold and respin in 5,154, which is about 1 paid spin in 523,407. A feature shows at least one Mini about 1 time in 4.8, a Minor 1 in 9.2 and a Major 1 in 27. Most of what locks is small: 82% of Embers carry 1, 2 or 3 times the bet, the average feature ends with 7.6 Embers and pays 31 bets, and 44% of features pay less than 20.
Does the respin counter resetting mean the feature is going well?
No. A reset means one Ember landed, and it gives 3 more respins at the same 3.5% chance per empty position. It feels like progress because the count goes up, but the board is only one prize larger and that prize is usually a small one. Five Embers in view on a normal spin works the same way: it looks one short of the feature, it turns up on 1.6% of spins, and it pays nothing.
Does autoplay change the odds?
No. Every spin is drawn the same way and the return stays 96.43% at the smallest bet. What autoplay changes is speed: more spins fit into an hour, and the cost of an hour is the number of spins times the 3.57% the machine keeps on each. That is why autoplay here will not start without a loss limit, and why it stops after a hold and respin or free spins.
What is the most a spin can pay?
2,500 times the bet. At the smallest bet that is the Grand plus a board of 15 Majors, and a round is cut off there. A round that pays 100 times the bet or more comes up about once in 1,958 spins. Almost all of the machine's return arrives in far smaller payouts.

How this game works

Each reel is a fixed strip of symbols, 43, 44, 44, 44, 44 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. There are 161,168,128 ways the five reels can stop. An Ember's prize is drawn from a fixed table of weights, shown in the pay table under the machine. In the hold and respin each empty position lands an Ember with a 3.5% chance on each respin, independently of every other position. On a free spin the two outer reels are strips of 43 and 43 symbols and the giant symbol is drawn by weight: a giant Caldera 5% of the time, a giant Ember 2% and a giant wild 1%.

Every figure on this page is counted, not simulated. Each of those combinations is priced against the pay table and filed by the Embers and Calderas it shows. The hold and respin is solved exactly as a chain over how many positions are locked and how many respins are left, which gives the chance of ending on every count from 6 to 15 and of every total the board can add up to. A free spin is priced for every stop of its outer reels against every giant symbol, and the number of spins in a bonus is solved the same way. Put together they give the exact chance of every total a round can pay. An automated test repeats the screen count one combination at a time through the same code the machine plays with, recounts every published figure, and plays 800,000 seeded rounds of the machine itself against them. The house edge on the common casino bets puts the 3.57% this machine keeps in context.

From that distribution at the smallest bet: 27.2% of spins pay anything, 10.3% pay something smaller than the bet, and 13.1% pay more than the bet. The spread of one spin's result has a standard deviation of 5.39 bets, which is the size of the swings around the average and is what makes this a medium volatility machine. Of everything it pays back, 61% comes from lines and Calderas on paid spins, 28% from the hold and respin, and 12% arrives during free spins (a feature started by a free spin is counted in both of the last two). The Grand itself is 0.20% of the return at the smallest bet and 0.02% at the largest.

The four tiers are fixed. Mini, Minor and Major are 20, 50 and 100 times the bet, and the Grand is 20,000 chips whatever the bet. Nothing is pooled between players and nothing grows: there is no progressive prize on play chips. A full board comes up in about 1 feature in 5,154, or 1 paid spin in 523,407, and a Major somewhere in a round about 1 paid spin in 3,135. Free spins start on about 1 paid spin in 346, run 7.0 spins on average and pay 39 bets on average.

The expected figure in the session panel is the share the machine keeps at your bet 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, prize weights and pay table were designed for this page. They are not a copy of Cash Eruption or of any other real machine, and these figures describe this machine only.
  • Cash Eruption is IGT's game and its name belongs to its owner. Caldera Cash is an independent alternative built on the same kind of mechanic. It is not made, licensed or endorsed by IGT.
  • The prize tiers here are fixed amounts, and the Grand is 20,000 play chips at every bet. Nothing is pooled or progressive, and none of it can be cashed out.
  • 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 are stopped 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 Cash Eruption 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: the sources we checked do not show that Cash Eruption has one. There is no bonus buy and no gamble feature either.
  • Play chips do not feel like money. A long blank run, or a feature that stops one position short, is harder to sit through and to stop after with a real stake.

This is a practice game for adults. It has no real-money play and links to none. Cash Eruption, or any slot played with money, keeps its share of every spin, and no way of timing or sizing the spins changes that. On this machine 38% of the spins that pay anything still cost more than they return, and the board that pays the Grand fills about once in 523,407 spins.

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

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