Kelly criterion gambling: staking in crash games

By · Last updated 31 October 2026

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On this page
  1. What the Kelly formula says about crash
  2. How the Kelly criterion system works
  3. Kelly criterion simulator test in rand
  4. What Kelly criterion does well
  5. Kelly criterion vs other betting systems
  6. Best games for Kelly criterion
  7. Run Kelly criterion in South Africa

The Kelly criterion strategy in crash games is simple: stake a fixed share of your current balance, so bets shrink after losses and grow after wins. It is a proportional sizing system that pairs naturally with a 2x auto cash out in Aviator, Stake Crash or JetX. In our 1,000-session test with R50 units it finished with a median of R2,354 from R2,500, with the top 10% on R2,993 or more. Here’s how to run it at Hollywoodbets, Betway or a partner crypto casino, with rand examples. More systems in our crash game strategy guide.

What the Kelly formula says about crash

The Kelly criterion sizes a bet as f = (b × p − q) ÷ b, where b is the net payout, p the win chance and q the loss chance. At a 2x target with 97% RTP, b = 1, p = 0.485 and q = 0.515, so f = −0.03. A negative answer means “don’t bet”: strict Kelly is built for bets with an edge. What crash players take from it is the idea of proportional staking: bet a small, fixed share of your current balance. That is what our simulator’s proportional mode does, at 2% (R50 from R2,500).

How the Kelly criterion system works

The rule: stake a fixed share of your current balance, so bets shrink after losses and grow after wins. Here is how six rounds play out at 2x auto cash out with a R50 unit:

Round Stake Result Running profit
1 R50 Loss −R50
2 R49 Loss −R99
3 R48.02 Win at 2x −R50.98
4 R48.98 Loss −R99.96
5 R48 Win at 2x −R51.96
6 R48.96 Win at 2x −R3

The stake moves with your results, which is the whole idea: the system decides your next bet so you never have to.

Kelly criterion simulator test in rand

We ran the Kelly criterion system at 2x through our simulator: 1,000 sessions of 100 rounds, a R2,500 bankroll and R50 bets. The median session finished on R2,354, the luckiest 10% on R2,993 or more and the coldest 10% on R1,852 or less. Not one session went bust. For comparison, flat R50 bets at 2x finished on a median of R2,400 with 0% busts. Try your own settings in the crash game simulator.

What Kelly criterion does well

  • You can never bust in theory: the stake always shrinks with the balance.
  • Swings stay as smooth as flat betting.
  • Wins compound automatically as the balance grows.

Worth knowing:

  • The textbook Kelly formula says to bet 0% on any game with a house edge, so crash players use a small fixed share instead (2% here).
  • Stakes need rounding to the casino’s minimum bet.

Kelly criterion vs other betting systems

System (2x, R2,500 bankroll) Median finish Top 10% finish Bust rate
Kelly criterion R2,354 R2,993 0%
Martingale R2,300 R5,100 46.5%
Anti-Martingale R2,300 R3,600 1.1%
Flat betting R2,400 R3,000 0%
Fibonacci R3,150 R3,700 31.5%

The Martingale strategy crash guide covers the doubling system, and anti Martingale crash covers pressing your wins. For the full ranking, read best betting system for crash games.

Best games for Kelly criterion

Use it on any crash game with auto cash out at 2x: Hollywoodbets Aviator is the classic, Stake Crash pays 99% RTP, and JetX South Africa lets you run two bets at once.

Run Kelly criterion in South Africa

Write your unit size down before you start (R50 is a good default on a R2,500 budget) and fund with Ozow instant EFT, 1Voucher or OTT Voucher. Want to play crash games with big-multiplier crypto originals and fast payouts? Compare the best crash game casinos in South Africa, or jump straight into Shuffle Crash.

Pro tip: set a session cap of 100 rounds and a stop at +20%; Kelly criterion is at its best in short, planned sessions.

Strategy simulator

Example: 1000 sessions of 100 rounds, bankroll R 2 500, base bet R 50, target 2x, 3% edge

StrategyMedian final bankrollUnlucky (10th percentile)Lucky (90th percentile)Chance of going bust
Proportional (Kelly-style)R 2 354R 1 852R 2 9930,0%
Fixed betR 2 400R 1 800R 3 0000,0%

Run it a few times with different settings to find the approach that fits your bankroll and playing style.

Top crash games

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Frequently asked questions

How does the Kelly criterion strategy work?

Stake a fixed share of your current balance, so bets shrink after losses and grow after wins.

Does Kelly criterion work in Aviator?

It runs fine with a 2x auto cash out. It shapes your swings; it cannot change the 97% RTP.

What unit size should I use for Kelly criterion?

About 2% of your budget, for example R50 on R2,500.

How risky is Kelly criterion?

In our 1,000-session test at 2x, 0% of sessions ran out of bankroll within 100 rounds.

Is Kelly criterion better than Martingale?

Kelly criterion finished with a median of R2,354 against Martingale's R2,300 in the same test.

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Daniel Foster

By · Crash Game Maths & Mechanics Analyst

Daniel focuses on the mathematics and mechanics behind crash games. His reviews examine RTP disclosures, volatility, multipliers, game mechanics and the mathematical principles behind different crash titles.

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