Why -105 Is a Bigger Deal Than It Looks (Compounding)
Main question: Why is -105 such a big deal (even compared to -110), and how does compounding make small pricing edges matter?
Quick answer
A fair line (no-vig / true-price benchmark) removes sportsbook margin so you can compare prices cleanly. In fast or wide markets, use fair lines to decide whether to shop, size smaller, or pass.
Fast benchmark for two-outcome markets: Fair Line Finder (2-Way).
Step-by-step: remove the juice (2-way)
- Convert posted odds → break-even probability.
- Measure market cost (implied sum/hold).
- Normalize to a fair benchmark (no-vig).
- Choose: shop / size / pass.
Use Fair Line Finder (2-Way) near the top for speed, then confirm with a second book if you can.
-105 lowers the hurdle rate
At -110 you need to win about 52.38% to break even. At -105 it’s about 51.22%. That difference is small per bet—but huge over volume.
Compounding is the hidden effect
Even a tiny improvement in pricing increases your long-run EV and reduces variance drag. Think of it like lowering the “tax” on every wager you make.
Where -105 shows up in the real world
Reduced-juice books, promos, and some high-liquidity markets. Fair-line benchmarking helps you see when -105 is real value versus when another part of the menu is widened.
Tools that pair well with this
- Odds Implied Probability (break-even).
- Hold/Overround Calculator (market cost).
- Fair Line Finder (2-Way) (fast benchmarks).
- Fair Line Finder (3-Way) (1X2-style benchmarks).
- Bankroll Tracker (process + review).
Worked example (with numbers)
Example prices:
- Option A: -107
- Option B: -103
Break-even (posted): A ≈ 51.69%, B ≈ 50.74%. The implied sum is 102.43% (your built-in toll).
Fair (no-vig) benchmark: A ≈ 50.46%, B ≈ 49.54% (sums to 100%).
Interpretation: if another book’s break-even rates sit closer to the fair benchmark on the same market, that’s usually cheaper execution.
Replicate this quickly using Fair Line Finder (2-Way), then decide whether the price improvement is worth the click.
Proof/check: break-even delta
- Compute break-even at -110 and -105.
- Multiply the delta by your weekly bet volume.
- That’s how much “tax” you remove just by shopping for -105.
How to use it (decision)
- Shop: when you can find meaningfully closer-to-fair pricing elsewhere.
- Size smaller: when menus are wide, lines are moving, or horizon/variance is high.
- Pass: when rules are unclear or pricing is clearly premium.
Related pages in this fair-line hub
- Wait For Normalization
- Line Shopping With Fair Lines
- Best Book Market Dependent
- Live Liquidity Margin
- Live Betting Checklist
Next step
Run the same benchmark check on two books for five snapshots this week. Your own data will tell you which menus quietly overcharge you.
Execution rules that actually help
- Confirm the ruleset before pricing.
- Shop at least one alternative book when possible.
- If you can’t shop, reduce stake.
Mini log (30 seconds)
- Market + timestamp
- Your price
- Implied sum / hold
- Fair benchmark
- Decision (shop/size/pass)
When “pass” is the correct answer
If the menu is clearly widened, information is incomplete, or you’re rushing, passing is often the highest-EV decision. Saving bullets is a skill.
What “implied sum” is telling you
The implied sum (or overround) is the market’s built-in toll. In live and props, that toll often spikes when books are protecting against uncertainty.
How to avoid fake precision
Don’t over-trust a fourth decimal place. In fast markets, treat no-vig outputs as a benchmark range and focus on directionally better prices and cleaner execution.
Execution rules that actually help
- Confirm the ruleset before pricing.
- Shop at least one alternative book when possible.
- If you can’t shop, reduce stake.
Mini log (30 seconds)
- Market + timestamp
- Your price
- Implied sum / hold
- Fair benchmark
- Decision (shop/size/pass)
When “pass” is the correct answer
If the menu is clearly widened, information is incomplete, or you’re rushing, passing is often the highest-EV decision. Saving bullets is a skill.
What “implied sum” is telling you
The implied sum (or overround) is the market’s built-in toll. In live and props, that toll often spikes when books are protecting against uncertainty.
How to avoid fake precision
Don’t over-trust a fourth decimal place. In fast markets, treat no-vig outputs as a benchmark range and focus on directionally better prices and cleaner execution.
Execution rules that actually help
- Confirm the ruleset before pricing.
- Shop at least one alternative book when possible.
- If you can’t shop, reduce stake.
Mini log (30 seconds)
- Market + timestamp
- Your price
- Implied sum / hold
- Fair benchmark
- Decision (shop/size/pass)
When “pass” is the correct answer
If the menu is clearly widened, information is incomplete, or you’re rushing, passing is often the highest-EV decision. Saving bullets is a skill.
What “implied sum” is telling you
The implied sum (or overround) is the market’s built-in toll. In live and props, that toll often spikes when books are protecting against uncertainty.
How to avoid fake precision
Don’t over-trust a fourth decimal place. In fast markets, treat no-vig outputs as a benchmark range and focus on directionally better prices and cleaner execution.
Execution rules that actually help
- Confirm the ruleset before pricing.
- Shop at least one alternative book when possible.
- If you can’t shop, reduce stake.
FAQ
What’s the break-even at -105?
About 51.22% for a two-way bet.
Is -105 always better than -110?
Yes on price, but check the rest of the menu—sometimes reduced juice is paired with other widened lines.
Where does -105 show up most?
Reduced-juice books, select markets, and sometimes during promotions.
How do I make this actionable?
Make -105 your default target when you’re shopping mainline markets.
Responsible note: pricing tools reduce margin and improve decision quality, but they don’t guarantee profit.