Kelly Calculator (stake as % of bankroll)
Find the optimal share of your bankroll to stake using the Kelly Criterion.
Stake % of capital
🧠 Staking strategy
Fixed stake as % of capital, identical for each bet
💎 Stake to place
Recommended stake
20.00€
That's 2% of your capital of 1000.00€
CalculaBet.com
📚 Full guide
Money management
Flat betting vs Kelly — finding the optimal stake for your strategy
💰Why manage your stake?▼
Bankroll management is what separates pro bettors from amateurs. Whatever your strategy, if you manage your stakes badly, you'll end up at zero.
The fundamental principle: never stake too high a % of your bankroll on a single bet. Even with a positive ROI, variance can knock you down if you stake too big.
Two main approaches:
- Flat Betting: fixed stake in % (e.g. always 2%). Simple and robust.
- Kelly: variable stake based on the edge. Mathematically optimal but more volatile.
📐Flat Betting — simple and effective▼
Staking a fixed % of your bankroll on each bet, regardless of the odds or confidence.
Advantages
✓ Simple to apply ✓ Resilient to bad streaks ✓ Impossible to burn your BR in one day ✓ Ideal when you don't know your probabilities precisely
📊 Benchmarks
→ 1% of BR: ultra cautious (beginner amateur)
→ 2% of BR: recommended standard (Pinnacle, Unibet)
→ 3% of BR: moderate (confirmed bettor)
→ 5% of BR: aggressive (high risk)
→ > 10% of BR: reckless, you'll burn your BR
With 2% of BR, it takes 50 consecutive losses to lose everything. Very unlikely even in a cold phase.
🧠Kelly Criterion — mathematically optimal▼
The Kelly Criterion is a mathematical formula that calculates the optimal stake to maximize the growth of your bankroll in the long run.
f* = (b × p - q) / b
b = odds - 1 (net gain)
p = your estimated probability
q = 1 - p
Concrete example: odds 2.00, you estimate a 55% chance of winning.
b = 2.00 - 1 = 1.00
p = 0.55, q = 0.45
f* = (1 × 0.55 - 0.45) / 1 = 0.10 = 10%
→ Full Kelly = stake 10% of BR
But Full Kelly is extremely volatile. Pros almost always use Half Kelly or Quarter Kelly.
⚖️Full, Half, Quarter Kelly — what's the difference?▼
🔥 Full Kelly (f*)
Maximum theoretical growth BUT enormous variance. A slightly wrong probability estimate and you can ruin your BR. Not recommended in practice.
⚖️ Half Kelly (f*/2) — RECOMMENDED
75% of Full Kelly's growth with only 50% of the variance. The best compromise in practice. Used by pros.
🛡️ Quarter Kelly (f*/4)
Ultra cautious. Slower growth but very low variance. Ideal if you're not sure of your estimated probabilities.
Golden rule: in sports betting, your estimated probabilities always have a margin of error. Half or Quarter Kelly compensate for this imprecision.
🔀Flat or Kelly — which to choose?▼
📐 Use Flat if...
- You're starting out or are a recreational bettor
- You follow tipsters (not your own probabilities)
- You can't estimate precise probabilities
- You want simplicity above all
🧠 Use Kelly if...
- You're an advanced bettor with a rigorous method
- You do value betting (your probabilities vs bookmaker)
- You want to maximize the growth of your BR
- You accept more short-term volatility
Pro tips
📌 Limit each stake to max 5% of BR, even with Kelly
📌 Recalculate your BR monthly — your stakes evolve with it
📌 Half Kelly is almost always the best choice
📌 Your estimated probabilities are ALWAYS imprecise — fraction Kelly
📌 On high odds (>4.00), Full Kelly becomes very risky
📌 Beginners: 2% flat is perfect for 6+ months
📌 Don't mix betting BR and personal money: strict separation