Stake sizing matters as much as picking. Use a fixed bankroll allocation and fractional Kelly. Most retail bettors over-size; serious bettors under-size and grow longer. Here's the framework.
Set a Bankroll
A bankroll is the amount of money you've allocated SPECIFICALLY for sports betting. Treat it as a fixed pool. Don't add unless rebalancing; don't withdraw except per a documented schedule.
Common rules of thumb:
Bankroll should be money you can afford to lose. If losing it would impact your life, the bankroll is too big.
Most casual bettors should start with $200-1000.
Keep your bankroll separate from daily money in a sportsbook account.
Use Units, Not Dollars
1 unit = 1% of bankroll. A $1000 bankroll has $10 units. This decouples stake size from bankroll variance, your unit value adjusts as bankroll grows or shrinks. Most professional models recommend stakes in units, not dollars.
Use Fractional Kelly
Kelly criterion gives the mathematically optimal stake, but full Kelly assumes your probability is exact, which it never is. Fractional Kelly trades growth rate for reduced variance:
Full Kelly: Maximum long-run growth IF prob is exact. Real bankroll variance is wild.
1/2 Kelly: 75% of full Kelly's growth, 25% of the variance (50% of the standard deviation).
1/4 Kelly: about 44% of full Kelly's growth, about 6% of the variance (25% of the standard deviation). Standard for verified models.
1/8 Kelly: about 23% of full Kelly's growth, under 2% of the variance (12.5% of the standard deviation). Bookie Bullies' default.
Why Bookie Bullies Uses 1/8 Kelly
The model has noise. Calibration is unproven on a per-bucket basis. 1/8 Kelly with variance adjustment limits drawdown risk while still sizing meaningfully on high-conviction picks. As track record matures and CLV is verified, the fraction can step up to 1/4 Kelly.
Practical Stake Schedule
Most picks: 0-3 units. Locks get no separate stake tier: every stake is 1/8-Kelly, capped at 5u. Avoid betting more than 5u on any single pick. The bankroll calculator on the Bookie Bullies homepage card converts units to dollar stakes for your input bankroll.
What to Avoid
Chasing losses. Increasing stakes after a losing day amplifies drawdown. Stick to your fractional Kelly schedule.
Doubling bankroll commitment after wins. Stake size scales WITH your unit value as bankroll grows; don't accelerate manually.
Going over 5% bankroll on a single bet. No matter how confident, single-pick variance can crater bankroll fast.
Mixing recreational + sharp bankrolls. Track each separately if you also play "for fun" bets.
Bankroll Math Examples
$1000 bankroll, +5% bankroll growth per month: compounds to about 16% per quarter and about 80% per year (1.05^3 and 1.05^12).
$1000 bankroll, +5% ROI but 5u/bet: 5x the stake means 5x the swings (25x the variance). 30%+ drawdowns are common in bad months.
$1000 bankroll, full Kelly on 60% picks: at even money that is 20% of bankroll per bet. Even if the 60% is exactly right, about 4 in 10 simulated 100-bet runs drop below half the starting bankroll at some point, and if the true rate is lower the damage gets much worse.