Why Taking the Best Odds Matters, Part II: What If You Sized Your Bets Correctly?
December 2, 2025

The Setup
In Part 1, we ran a simulation of 1000 bets comparing two scenarios:
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Best Book Odds: Taking the best available line and sizing with Kelly
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“Your Odds”: Taking suboptimal odds but using the same Kelly sizing as Best Book (simulating that you were tailing someone at their same recommended units, even though you got a worse price)
The results were brutal. Best Book finished at +21.78 units. Your Odds finished at -25.93 units. A 47.71 unit swing - same opportunities, just worse execution.
But here's the question that came up: What if you properly adjusted your bet sizing for the odds you were actually getting?
The Fix: Recalculate Kelly for YOUR Odds
The problem in Part 1 wasn't just taking worse odds - it was using the wrong bet sizing for those odds.
When the Value Finder shows 0.5u at +360, that sizing is calculated for +360. If you take +320 instead, the correct move is to recalculate Kelly for +320.
Here's what that means in practice:
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If the recalculated Kelly is still positive → bet that amount (smaller than the original recommendation)
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If the recalculated Kelly is zero or negative → don't bet at all
The Part 2 Simulation
I ran the same 1000 bets, same outcomes, but added a third scenario:
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Best Book Odds - Full Kelly at best available odds (same as Part 1)
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Your Odds (Wrong Sizing) - Using Best Book Kelly at worse odds (Part 1)
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Your Odds (Proper Kelly) - Recalculating Kelly for the actual odds taken
The Results
Best Book Odds
- Final Profit: +21.78 units
- Bets Taken: 1000
- ROI: 5.2%
Your Odds (Wrong Sizing)
- Final Profit: -25.93 units
- Bets Taken: 1000
- ROI: -6.2%
Your Odds (Proper Kelly)
- Final Profit: +5.04 units
- Bets Taken: 254 (25.4%)
- Bets Skipped: 746 (74.6%)
- ROI: 15.8%
The Transformation
Look at what happened:
Wrong sizing: -25.93u (LOSING)
Proper sizing: +5.04u (WINNING!)
That's a 30.97 unit improvement - just from sizing your bets correctly!
Why This Works
Remember from Part 1: 74.6% of the bets went from +EV to -EV when you took suboptimal odds.
With proper Kelly sizing, those 746 -EV bets become 0 unit bets. You don't take them. Kelly is telling you: "At these odds, this bet has no edge. Pass."
The remaining 254 bets are still +EV at Your Odds - just with a smaller edge. Proper Kelly sizes them down appropriately.
The result? You:
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Skip 746 losing bets entirely
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Size the remaining 254 bets correctly for their actual edge
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Turn a -25.93u disaster into a +5.04u profit
The Trade-Off
There's a catch. Look at the total action:
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Best Book: 419.57 units risked
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Your Odds (Proper Kelly): 31.95 units risked
By only taking the 254 remaining +EV bets at proper sizing, you're betting 92% less money.
This is a cost of not having access to best odds. It's not just that you make less per bet - you have far fewer bets worth taking.
What This Means for You
If you can access the best book:
Take all the opportunities at full recommended sizing. You're maximizing your edge and your action.
If you can only get worse odds:
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Recalculate Kelly for your actual odds
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Skip bets where the new Kelly is zero or negative
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Size down the remaining bets appropriately
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Accept that you'll have less action overall
The honest truth:
Proper Kelly with worse odds (+5.04u) is still WAY better than wrong Kelly with worse odds (-25.93u). But it's not as good as Best Book (+21.78u).
The math is unforgiving. Worse odds = smaller edge = fewer bets worth taking = less profit.
The Bottom Line
Can you salvage a bad situation with proper sizing?
Yes. Absolutely. Going from -25.93u to +5.04u is a massive improvement. Proper Kelly sizing turned a losing bettor into a winning one.
But you're still leaving money on the table.
Best Book: +21.78u
Your Odds (Proper): +5.04u
Difference: 16.74u
That 16.74 units? That's the cost of not having access to the best lines - even when you do everything else right.
The Takeaway
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Best case: Take best odds at full sizing → +21.78u
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Salvageable: Take worse odds but size properly → +5.04u
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Worst case: Take worse odds with wrong sizing → -25.93u
If you can't get the best odds, at least get your sizing right. But the real play? Get accounts at the books with the best lines.
This is Part 2 of our odds education series. I recommend reading Part 1 to understand why taking suboptimal odds costs you money.
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