Most AFL bettors lose not because their analysis is poor, but because their bankroll management is non-existent. They bet too much on games they feel strongly about, too little on games where the value is highest, and nothing consistently enough to let the edge compound. This guide covers the three pillars of sustainable betting: bankroll structure, expected value, and closing line value.
Setting Up a Bankroll
A bankroll is a fixed amount of money set aside exclusively for betting. It is not rent money, savings, or disposable income that changes week to week. It is a defined pool that exists to be wagered on positive-expectation opportunities over a full season.
The first step is to set a bankroll amount you can afford to lose entirely. This is not pessimism - it is risk management. Even a skilled bettor with a genuine edge can experience drawdowns of 30–50% of their bankroll over a bad stretch. If the bankroll is money you need, those drawdowns will force emotional decisions that destroy the edge.
A common starting bankroll for a recreational AFL bettor is $500–$2,000. For more serious bettors, $5,000–$10,000. The amount matters less than the discipline to treat it as a fixed pool and bet in units relative to it.
Unit Sizing
A unit is the standard bet size, typically 1–2% of the bankroll. If the bankroll is $1,000, one unit is $10–$20. This keeps individual bets small enough that a losing streak does not destroy the bankroll, while large enough that winners are meaningful.
The unit size should reflect confidence and edge size:
- 1 unit: Standard bet. The analysis shows value, but the edge is moderate.
- 1.5 units: Strong conviction. Multiple indicators align and the price is clearly wrong.
- 2 units: Maximum bet. Reserved for the strongest plays of the round - clear mispricing with high confidence.
- 0.5 units: Speculative or high-variance bets - SGMs, player props, or futures where the edge is real but the outcome is uncertain.
Never exceed 2 units on a single bet. Never bet more than 5% of the bankroll on any single round. These limits exist to survive the inevitable losing runs that even the best process produces.
The Kelly Criterion (Simplified)
The Kelly Criterion is a formula that calculates the optimal bet size based on your edge and the odds. The full formula is: f = (bp - q) / b, where f is the fraction of bankroll to bet, b is the decimal odds minus 1, p is the estimated true probability, and q is 1 minus p.
In practice, full Kelly is too aggressive for most bettors. It produces large bet sizes that amplify variance. Most professional bettors use quarter-Kelly or half-Kelly - dividing the Kelly-recommended stake by 2 or 4. This reduces volatility significantly while still capturing most of the long-term growth.
Example: If a team is priced at $2.20 (b = 1.20) and you estimate their true probability at 50% (p = 0.50, q = 0.50), full Kelly says bet (1.20 × 0.50 - 0.50) / 1.20 = 8.3% of bankroll. Quarter-Kelly says bet about 2.1% - roughly 1 unit on a standard bankroll. This feels about right for a moderate edge.
Expected Value (EV)
Expected value is the average profit or loss on a bet if it were placed an infinite number of times. It is the single most important concept in betting mathematics.
The formula is: EV = (probability × profit) - ((1 - probability) × stake).
If a team has a true 50% chance of winning and the odds are $2.20, the EV on a $10 bet is: (0.50 × $12) - (0.50 × $10) = $6.00 - $5.00 = +$1.00. This is a positive-expectation bet. Over 100 such bets, you would expect to profit approximately $100.
If the same team is priced at $1.80, the EV becomes: (0.50 × $8) - (0.50 × $10) = $4.00 - $5.00 = -$1.00. This is a negative-expectation bet. The team might still win, but the price does not justify the risk.
The discipline is simple: only place positive-EV bets. Walk away from everything else, no matter how confident the pick feels.
Closing Line Value (CLV)
Closing line value is the difference between the price you took and the price at which the market closes just before the game starts. It is widely regarded as the single best predictor of long-term betting success.
If you back a team at $2.20 on Wednesday and the closing price on Saturday is $2.00, you achieved positive CLV. The market moved toward your position, confirming that your early price was better than the final consensus. If the price moved from $2.20 to $2.40, you achieved negative CLV - the market moved away from you, suggesting the early price was not as good as it appeared.
Why does CLV matter more than win rate? Because the closing line is the most efficient price the market produces. It incorporates all available information - late team news, weather updates, money from professional bettors. Consistently beating the closing line means consistently getting better prices than the sharpest money in the market. Over hundreds of bets, positive CLV almost always translates into profit, regardless of short-term win/loss variance.
Tracking Your Results
No bankroll management system works without tracking. Every bet should be recorded with: date, match, market, selection, odds taken, stake (in units), result, profit/loss, and closing price. A simple spreadsheet is enough.
Review the data at the end of each month and at mid-season. Look for patterns: Which markets are most profitable? Which bet types have the best CLV? Are there games or situations where the process consistently fails? The answers to these questions improve the process for the second half of the season.
The most important metric to track over a season:
- ROI (Return on Investment): Total profit divided by total amount wagered. A positive ROI means the process is working. An ROI above 3–5% over a full season is strong.
- Yield: Similar to ROI but expressed per bet. Total profit divided by number of bets times average stake. Yield above 5% is excellent.
- CLV average: The average difference between price taken and closing price across all bets. Positive CLV average is the strongest signal of genuine edge.
- Win rate by market: Track hit rates for H2H, line, totals, props, and SGMs separately. Some bettors are sharper in certain markets.
Emotional Discipline
The hardest part of bankroll management is not the maths. It is the discipline to follow the rules during losing streaks. A 10-bet losing run is not unusual even with a genuine edge. During those periods, the temptation is to increase stakes ("to win it back"), chase losses with long-odds multis, or abandon the process entirely.
The correct response to a losing streak is to review the process, confirm the CLV data, and continue at the same unit size. If the process is sound and CLV is positive, the results will come. If the process has a flaw, the review will reveal it. Either way, increasing stakes during a drawdown is the single fastest way to go broke.
