In Roulette, not all bets are created equal. While the House Edge remains constant (2.70% for European, 5.26% for American), the risk to your bankroll changes drastically depending on where you place your chips.
A player betting on “Red” experiences gentle swings, while a player betting on “Number 7” faces violent variance. Our Roulette Bankroll Calculator adjusts for volatility by bet type, showing you the probability of finishing your session at or below $0 based on your specific playing style and session length.
Important: this calculator uses exact binomial probability for flat betting (same bet every spin). It calculates the chance of finishing the session broke, not the chance of hitting $0 at any point during the session (which would be higher). It does not model progressive systems like Martingale — for that, see our Martingale Simulator.
Roulette Bust Calculator
☸How to Use the Roulette Bankroll Calculator
This tool helps you visualize session risk before you sit down at the table. Here is how to configure it:
- Enter Financials: Input your total Bankroll (the money you are willing to lose) and your flat Bet Per Spin.
- Select Game Version:
- Choose European (Single Zero) whenever possible. It has a significantly lower house edge than American (Double Zero).
- Select Bet Type: This is the key input that drives the volatility calculation.
- Low Volatility: Red/Black, Odd/Even (1:1 payouts). Wins occur frequently (~48.6%).
- High Volatility: Straight Up (35:1 payouts). Wins are rare (~2.7%), requiring a much larger bankroll to survive the gaps between hits.
- Analyze the Results:
- Chance of finishing broke: The exact probability that your ending balance is at or below $0 after N spins. If this is above 20%, your bet size is too large for your bankroll — or your bet type is too volatile.
- 95% Range: The lower and upper bounds within which roughly 95% of sessions will end.
- Expected Loss: The mathematical cost of the house edge over your session.
Related tools: to analyze Martingale and other progressive systems, use the Martingale Simulator. To understand the probability of a specific streak (e.g., 10 reds in a row), use the Streak Calculator. For general session probability math, see the Probability After N Attempts Calculator.
Why Volatility Matters More Than House Edge
The house edge tells you how much you lose on average per dollar wagered. But it does not tell you how your session will feel. Two players betting $5 per spin on European Roulette lose the same $13.51 on average over 100 spins. But their experiences are completely different:
| Bet Type | Payout | Win Freq | Expected Loss | P(finish broke) |
|---|---|---|---|---|
| Red/Black | 1:1 | 48.6% | −$13.51 | 0.01% |
| Column/Dozen | 2:1 | 32.4% | −$13.51 | 0.4% |
| Six Line | 5:1 | 16.2% | −$13.51 | 5.4% |
| Corner | 8:1 | 10.8% | −$13.51 | 7.5% |
| Street | 11:1 | 8.1% | −$13.51 | 17.0% |
| Split | 17:1 | 5.4% | −$13.51 | 20.5% |
| Straight Up | 35:1 | 2.7% | −$13.51 | 24.4% |
All figures: European Roulette, $200 bankroll, $5/spin, 100 spins. Expected loss is identical for all bet types — only the bust probability changes.
Real-World Examples
Example 1: The “Grinder” (Even Money)
You have $200 and bet $5 per spin on Red. You plan to play 100 spins.
- Volatility: Low.
- Chance of finishing broke: 0.01% — virtually impossible.
- 95% Range: $89 to $284.
- Verdict: Extremely safe session. Your balance will fluctuate gently around $186. You will almost certainly walk away with most of your money.
Example 2: The “Sniper” (Straight Up)
You have the same $200 and bet $5 per spin on Number 17. You play 100 spins.
- Volatility: Extreme.
- Chance of finishing broke: ~24% — roughly 1 in 4 sessions.
- 95% Range: $0 to $759.
- Verdict: Same bet size, same expected loss — but you have a 1 in 4 chance of losing everything and a small chance of walking away with 3–4× your starting bankroll. To play Straight Up with the same safety as Red/Black, you would need a bankroll roughly 10× larger.
Frequently Asked Questions (FAQ)
What is Volatility in Roulette?
Volatility (or Variance) measures how much your bankroll swings up and down. High volatility bets (like single numbers) pay out huge amounts but rarely, causing massive downswings between hits. Low volatility bets (like Red/Black) pay out small amounts frequently, keeping your balance stable. The house edge is the same for all bet types on the same wheel.
Why does American Roulette have a higher bust risk?
American Roulette adds an extra “Double Zero” (00) to the wheel. This increases the House Edge from 2.70% to 5.26%, which drains your bankroll roughly twice as fast as European Roulette and increases your probability of finishing broke over the same session length.
Does this calculator work for Martingale or other progressive systems?
No. This calculator assumes flat betting — the same bet amount every spin. Progressive systems like Martingale (doubling after a loss) have completely different risk profiles and require separate analysis. Use our Martingale Simulator for that.
What is a safe bet size?
A general rule for recreational play: bet no more than 1–2% of your session bankroll on even-money bets, and no more than 0.1–0.2% on Straight Up bets. Use the calculator to check — if the bust probability exceeds 10–15%, your bet size is too aggressive for your bankroll.
Is “chance of finishing broke” the same as “risk of ruin”?
Not exactly. This calculator estimates the probability of ending the session at or below $0. True “risk of ruin” — the chance of hitting $0 at any point during the session, even if you would have recovered — is a more complex calculation and produces a higher number. For practical session planning, the end-of-session probability is the more useful metric.
Why is the expected loss the same for Red/Black and Straight Up?
Because the house edge is the same regardless of bet type within the same wheel version — 2.70% for European. The expected mathematical loss over 100 spins at $5 per spin is always −$13.51. What changes is the volatility: Red/Black gives smooth, predictable results, while Straight Up gives extreme swings around the same average loss.