How crash games work: seeds, crash point and the odds behind Rocket Rush

By Marcus Vale · Slots & Maths Editor · Last verified October 24, 2026 · How we review

A crash game draws one hidden number, the crash point, before the multiplier starts to climb, and you win if you cash out below it. In Rocket Rush that number comes from a server seed whose hash is shown before the round, with a 3% house edge built into a single division. This guide shows the formula, how to check a real round yourself and why no cash-out rule changes the 97% return.

This article is part of our slot guides, written to explain the maths and mechanics behind every spin.

The table lists the chance that the rocket reaches each target. Every percentage is 0.97 divided by the target, taken from the server code behind Rocket Rush, and the time column follows the climb curve e^0.06·t with t in seconds.

Cash-out target	Chance the rocket gets there	Seconds after lift-off	Average return at that target
Busts at 1.00×	3.96%	0	no cash-out possible
1.50×	64.67%	6.8	97%
2×	48.50%	11.6	97%
3×	32.33%	18.3	97%
5×	19.40%	26.8	97%
10×	9.70%	38.4	97%
50×	1.94%	65.2	97%

Source: the round-generation code of the VegasSlots Originals, read on 24 October 2026. Play-money XP only.

How is a crash round generated?

Each round starts from a secret server seed. In Rocket Rush the seed is derived on the server from the round number and a key only the server holds, so nobody can compute it in advance. Before betting closes, the page receives the SHA-256 hash of that seed, which fixes the seed without revealing it.

After the rocket busts, the seed itself is published. Hash it and compare the result with the commitment shown earlier: if a single character had been swapped after betting, the two would differ. The round hash then joins three things with colons:

the server seed,
a client seed, which is the fixed text vegasslots-crash in Rocket Rush because one round is shared by every player,
the nonce, which is the round number.

Other Originals such as Neon Drop take a client seed from your browser. A shared crash round cannot, because everybody would have to agree on one value first.

What is the crash point formula, and where does the house edge sit?

The server hashes seed:client seed:nonce with SHA-256 and reads the first 13 hexadecimal digits as an integer h. That gives a number U between 0 and 1, and the return rate is divided by it.

U = 1 − h / 2⁵²

crash point = floor( max(1, 0.97 / U) × 100 ) / 100

U is uniform, so the chance that the crash point reaches a target x equals the chance that U is at most 0.97 / x, which is 0.97 / x. Multiply that by the payout x and you get 0.97 for every target. That is where the 3% edge sits.

The 3.96% of rounds that end at 1.00× are not an extra charge. They are the rounds where 0.97 / U falls below 1.01, a share of 1 − 0.97 / 1.01, and they are already inside the 97%.

How do you verify a round step by step on Rocket Rush?

You need the commitment hash from before the round and the seed from after it. Copy the hash while betting is open, because the check only proves something if you captured the hash first.

During betting, note the round number and the commitment hash shown on the Rocket Rush page.
After the bust, copy the revealed seed.
Hash the seed with SHA-256. The result must equal the commitment from step 1.
Hash the text seed:vegasslots-crash:round number and take the first 13 hex digits.
Compute U and the crash point with the formula above. It must equal the number the rocket stopped at.

The “Verify last round” button runs these steps in your browser. You can also run them yourself:

import hashlib, math
seed = "a6e584b3729287bad752cb6934ac0a070dc4995262b5edad4d73eba200de6415"
k = 139
print(hashlib.sha256(seed.encode()).hexdigest())   # = commitment
h = hashlib.sha256(f"{seed}:vegasslots-crash:{k}".encode()).hexdigest()
u = 1 - int(h[:13], 16) / 2**52
print(math.floor(max(1, 0.97 / u) * 100) / 100)

We ran exactly this on round 139 on 24 October 2026, using the public round data. The seed hashed to the commitment 66e083e4…2558084, U came out at 0.95320, and 0.97 / 0.95320 = 1.0176 floors to 1.01, the point the server reported.

Why can no strategy beat the house edge?

Every bet returns 97% of its stake on average, and bets do not influence each other. A strategy can change how much you stake and when you leave, never the 3% taken from each stake. The expected loss is 3% of everything you staked, so a plan that stakes more in total expects to lose more.

Doubling after every loss is the classic example. From the 5 XP minimum, stakes run 5, 10, 20 and so on to 2,560 XP on the ninth bet. The tenth would be 5,120 XP, above the 5,000 XP limit. At a 2× target, nine losses in a row happen with probability 0.515⁹, about 1 in 390 sequences, and that sequence cannot be recovered.

Waiting for a high number to be due does nothing, because the next seed is unrelated to the last.
Copying another player’s cash-out point copies their luck, not an edge.

Our RTP guide explains why a long-run percentage says little about one session, and the volatility guide covers how a spread of results feels.

How do real-money crash games differ?

The shape is the same: a hidden crash point, a rising multiplier and a house edge written into the formula. What changes is who vouches for fairness and what the stake is worth. Only general points are safe here, so read each game’s own rules page.

A licensed game normally publishes its RTP in the rules. Read that figure instead of assuming one.
Many licensed games rely on a random number generator tested by an independent lab and give you no seed to recompute.
Bonus terms often exclude crash games from wagering or weight them low.
Rules vary by market, and some regulators restrict features such as autoplay or very fast rounds.

Loss also scales with turnover. Staking 100 units on each of 120 rounds puts 12,000 through the game, and at a 3% edge the average loss is 360 units whatever targets you chose. The free Originals let you see that at no cost.

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Frequently asked questions

Is the crash point decided before I place my bet?

Yes. The seed for each round is fixed on the server, and its hash is shown before betting closes. Placing a bet does not change the seed.

Why do some rounds bust at 1.00×?

About 3.96% of rounds end there, because 0.97 / U falls below 1.01 and the result is floored to cents. A 1.01× target still returns 97% on average, since it wins in 96.04% of rounds.

Which auto cash-out target is best?

None is better on average. The expected return is 97% at 1.5× and at 50×. Choose by how often you want to win: 64.67% of rounds reach 1.5×, 1.94% reach 50×.

Does the previous crash point predict the next one?

No. Each round has its own secret seed and its own hash. A run of low numbers does not make a high one more likely.

Does a bigger stake change the odds?

No. The formula does not use the stake, which runs from 5 to 5,000 XP in Rocket Rush.

Playing responsibly

Rocket Rush and the other Originals are free and use play-money XP, but the same maths applies to real-money crash games, where a 3% edge on every round adds up quickly. You must be 18 or older to play for money. Set a deposit limit and a time limit before you start, never chase losses and stop when it is no longer fun. Our responsible gambling page lists support, and every regulated market has a free, confidential helpline.

More in the guides: Plinko odds and mines game maths, which you can try as Neon Drop and Vault Grid.

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