Martingale Calculator — Betting Strategy Risk Analysis

Enter your base stake (the starting bet amount), the multiplier (2 for standard Martingale), the decimal odds you are betting at, your estimated win probability, and your total bankroll. Click "Calculate Martingale Progression" to see the full step-by-step table.

The table shows what happens at each consecutive loss. For each step you can see the required stake, the total amount you have committed, the net profit if you win at that step, and the probability of even reaching that point. Rows highlighted in red indicate that your bankroll has been exhausted — you cannot place that bet.

Pay attention to the Edge Per Bet figure at the top of the results. This number does not change as you progress through the Martingale sequence. If it is negative at step 0, it remains negative at every subsequent step. Martingale rescales the bets; it does not alter the mathematics of each individual wager.

The Martingale sequence follows a geometric progression. With a base stake B, multiplier m, and decimal odds d:

1. Stake at step N: stake_N = B × m^N
2. Cumulative staked through step N: total_N = B × (m^N+1 − 1) ÷ (m − 1)
3. Net profit if you win at step N: profit_N = stake_N × d − total_N
4. Probability of reaching step N: P(reach N) = (1 − p)^N
5. Edge per bet: edge = p × (d − 1) − (1 − p)

For standard Martingale at exactly even-money odds (d = 2.0) with 50% win probability, the net profit at every step is exactly B — you always recover your base stake profit. However, this only holds at perfect 50/50 odds with no house edge. Real sportsbook odds at −110 (d ≈ 1.909) carry a built-in negative edge of roughly −4.55%, and no amount of bet sequencing changes that fundamental fact.

The expected loss per Martingale cycle (betting until your first win) equals the sum of the expected value across each step, weighted by the probability of reaching that step. Crucially, this simplifies to the same negative edge applied to the same expected total stake — which grows very rapidly as the multiplier compounds.

Example 1 — Standard Martingale at Even Money (d = 2.0, 50% win probability)

You bet $10 at 2.0 decimal odds, doubling after each loss. Your bankroll is $500.

• Step 0: bet $10, total risked $10, profit if win: +$10
• Step 1 (after 1 loss): bet $20, total risked $30, profit if win: +$10
• Step 2 (after 2 losses): bet $40, total risked $70, profit if win: +$10
• Step 3 (after 3 losses): bet $80, total risked $150, profit if win: +$10
• Step 5 (after 5 losses): bet $320, total risked $630 — exceeds $500 bankroll

You risk losing $630 for a potential gain of just $10. The probability of reaching step 5 with a 50% win probability is (0.5)⁵ = 3.125% — not negligible at all over a long session.

Example 2 — Sportsbook Odds at −110 (d = 1.909, 50% win probability)

Most US sportsbooks price sides at −110, meaning you must wager $110 to win $100. At 50% win probability, the edge per bet is 0.5 × 0.909 − 0.5 = −4.55%. Every step of the Martingale carries this same negative edge. Over 1,000 betting cycles, this compounds into devastating losses.

Example 3 — Why a Losing Streak Is Not "Due"

A fundamental cognitive error behind Martingale is the Gambler's Fallacy: the belief that after a sequence of losses, a win is "overdue." In reality, each bet is statistically independent. After five heads in a row, the probability of a sixth head is still exactly 50%. The coin has no memory. The roulette wheel has no memory. The dice have no memory. Your bets do not become more likely to win because you have already lost several times.