Betting Bankroll Management Calculator
Project your betting bankroll growth over a series of bets using your win rate, unit size, and staking strategy. Ideal for bettors who want to manage risk and grow their funds systematically.
About this calculator
Bankroll management determines how much of your total funds to risk per bet and forecasts how your balance grows (or shrinks) over time. The core formula used here is: Final Bankroll = Initial Bankroll + Number of Bets × [(Win Rate / 100) × (Unit Size / 100) × Initial Bankroll × (Average Odds − 1) − (1 − Win Rate / 100) × (Unit Size / 100) × Initial Bankroll]. This formula estimates average expected growth per bet and compounds it linearly across the total number of bets. The term (Average Odds − 1) represents the net profit per unit won, while (1 − Win Rate / 100) is the loss probability per bet. Unit size — expressed as a percentage of your bankroll — is the single most important variable: too large and a losing streak wipes you out; too small and growth is negligible. Most professional bettors recommend a unit size between 1% and 5%.
How to use
Assume a $1,000 bankroll, 2% unit size, 55% win rate, average decimal odds of 2.00, and 100 bets. Step 1 — unit value per bet: 2% × $1,000 = $20. Step 2 — profit per winning bet: $20 × (2.00 − 1) = $20. Step 3 — loss per losing bet: $20. Step 4 — expected gain per bet: (0.55 × $20) − (0.45 × $20) = $11 − $9 = $2. Step 5 — total projected final bankroll: $1,000 + 100 × $2 = $1,200. Your projected bankroll after 100 bets is $1,200, a 20% gain assuming flat staking.
Frequently asked questions
What is the recommended unit size percentage for sports betting bankroll management?
Most professional bettors recommend risking between 1% and 5% of your total bankroll per bet, with 2% being a widely cited standard. A 1–2% unit size allows you to survive extended losing streaks — statistically inevitable even for winning bettors — without going broke. Higher unit sizes like 5–10% increase short-term growth potential but dramatically raise the risk of ruin. Your ideal unit size depends on your edge, variance tolerance, and how confident you are in your win rate estimate.
How does win rate affect long-term betting bankroll growth?
Win rate is the percentage of bets you win and is the primary driver of whether your bankroll grows or shrinks. At average odds of 2.00 (even money), you need a win rate above 50% just to break even. Every percentage point above breakeven contributes directly to profitability. For example, a 55% win rate at 2.00 odds yields a 10% edge per bet — a significant long-term advantage. Accurately estimating your true win rate requires a large sample of bets, typically 500 or more, to filter out short-term variance.
What is the difference between flat staking and percentage staking strategies in betting?
Flat staking means betting a fixed dollar amount on every bet regardless of your current bankroll balance, making it simple and predictable. Percentage staking means betting a fixed percentage of your current bankroll, so your unit size adjusts up as you win and down as you lose. Percentage staking is generally preferred because it naturally reduces exposure during losing runs and accelerates growth during winning runs. However, it also means you can never technically hit zero — though you can get very close. The best strategy depends on your goals, discipline, and confidence in your edge.