#expectedvalue

Most bettors focus on who to bet.

Professionals focus on how much to bet.

Because even great picks fail when bet sizing is wrong.

Why Bet Sizing Matters More Than Picks

You can:

- Win 55% of your bets - Still lose money - Or go broke entirely

All because of poor sizing.

Bet sizing controls:

- Volatility - Drawdowns - Long-term survival

It’s the difference between variance and ruin.

The Most Common Bet Sizing Mistake

The biggest mistake bettors make:

Betting based on confidence instead of math.

Confidence is emotional. Math is structural.

When bet size changes based on “feel,” variance becomes lethal.

Flat Betting: The Foundation Strategy

Flat betting means:

- Same unit size - Every wager - Regardless of confidence

Typical flat bet sizing:

- 1–2% of bankroll per bet

Why it works:

- Controls drawdowns - Prevents emotional escalation - Survives long losing streaks

Flat betting doesn’t maximize upside — it maximizes longevity.

What Happens When You Bet Too Much

Overbetting leads to:

- Extreme swings - Emotional decision-making - Chasing losses - Bankroll collapse

A 10% bet size only needs a short losing streak to end everything.

Variance doesn’t care how confident you are.

The Kelly Criterion (And Why Most Bettors Misuse It)

Kelly betting sizes wagers based on perceived edge.

In theory, it’s optimal.

In practice:

- Edges are estimated poorly - Inputs are noisy - Errors compound quickly

Many bettors use fractional Kelly (¼ or ½ Kelly) to reduce risk — but only if their edge estimation is accurate.

Most bettors overestimate their edge.

Progressive Bet Sizing: Dangerous by Design

Systems that increase bet size after losses (Martingale-style):

- Assume losses will stop soon - Ignore tail risk - Magnify exposure at the worst time

Progressions don’t eliminate variance. They weaponize it against you.

A Simple Bet Sizing Framework

For most bettors:

- Define a bankroll - Risk 1% per bet - Never adjust mid-session - Review results only after large samples

This approach isn’t exciting — but it works.

Why Professionals Bet Small

Pros don’t chase:

- Big scores - Short-term streaks

They chase:

- Survival - Scalability - Long-term edge realization

Small bets allow them to stay in the game long enough for math to matter.

Bet Sizing and Psychological Control

Proper sizing:

- Reduces tilt - Prevents chasing - Keeps decision-making rational

If a loss hurts emotionally, the bet was too large.

Final Thoughts

Bet sizing is boring. That’s why it works.

The goal isn’t to win today — it’s to still be betting next year.

If you control bet size, variance becomes manageable. If you don’t, no system can save you. Bet sizing decisions must align with overall bankroll management principles.

Two bet sizing methods dominate serious betting discussions:

- Flat betting - The Kelly Criterion

Both are logical. Both are mathematical. Only one fits most bettors in the real world.

What Flat Betting Really Is

Flat betting means:

- Same bet size - Every wager - Independent of confidence

Usually:

- 1–2% of bankroll per bet

Flat betting assumes:

- You might have an edge - But you respect uncertainty - And you prioritize survival

It’s conservative by design.

What the Kelly Criterion Tries to Do

The Kelly Criterion sizes bets based on:

- Your estimated edge - The odds being offered

The formula attempts to:

- Maximize long-term bankroll growth - Avoid ruin if inputs are perfect

And that’s the problem.

Kelly Works Only If You Know Your True Edge

Kelly assumes:

- Accurate probabilities - Stable edges - Correct pricing

Most bettors:

- Overestimate their edge - Use small samples - Confuse variance with skill

A small error in edge estimation leads to massive overbetting.

Why Kelly Feels So Powerful (At First)

Kelly betting often:

- Starts fast - Grows aggressively - Produces impressive early curves

This is survivorship bias in action.

You don’t see:

- The blown-up bankrolls - The unrecoverable drawdowns - The bettors who quit

Volatility: The Hidden Cost of Kelly

Even correctly applied Kelly betting:

- Produces brutal swings - Creates deep drawdowns - Requires extreme emotional discipline

Many bettors abandon Kelly at the worst possible moment — after losses.

At that point, the math no longer matters.

Fractional Kelly: The Compromise

Some bettors use:

- ½ Kelly - ¼ Kelly

This reduces volatility but introduces a question:

If you’re cutting Kelly down to survive… Why not just flat bet?

Fractional Kelly slowly converges toward flat betting behavior anyway.

Why Professionals Prefer Flat Betting

Pros value:

- Stability - Scalability - Predictable risk

Flat betting allows:

- Clean performance analysis - Easier automation - Lower emotional load - Longer betting careers

Many “Kelly bettors” quietly flatten their bets over time.

Flat Betting Handles Bad Assumptions Better

When your edge estimate is wrong:

- Kelly magnifies the mistake - Flat betting absorbs it

Flat betting is error-tolerant. Kelly is not.

The Psychological Reality

Flat betting:

- Reduces tilt - Prevents chasing - Keeps losses manageable

Kelly betting:

- Encourages confidence-based sizing - Amplifies emotional reactions - Punishes hesitation

Most bettors are human — not equations.

Which One Should You Use?

For most bettors:

- Flat betting wins - Kelly adds unnecessary risk - Survival beats optimization

Kelly belongs in:

- Academic models - Simulations - Very controlled environments

Flat betting belongs in real bankrolls.

Final Verdict

If your goal is:

- Longevity - Emotional control - Sustainable growth

Flat betting is the better choice.