Betting odds truth calculator
The math the bookmaker hopes you never run. Convert odds, compute implied probability, and simulate your long-term result at the current line.
Your bet
= 2.00 · 1/1 · +100
Typical: 2–6% (major US/EU sports), 6–10% (niche sports), 15–40% (obscure markets). The sportsbook's cut is baked into these odds — slide to match your book.
What the odds mean
Implied probability
The bookmaker's price implies this chance of winning.
50.00%
Fair probability
After stripping out the assumed vig.
47.62%
If you win
+$10.00
If you lose
-$10.00
Expected value per bet
Over time, each bet costs you this on average.
$-0.48
Time-value check
If you place this exact $10 bet every week for a year:
Total staked
$520
Expected loss
-$24.76
Roughly equivalent to
a nice dinner out
"Free bet" deconstruction
Most "free bet" promos are stake-not-returned — only the winnings pay out. Combined with a minimum odds rule, the actual cash value is a fraction of the headline number.
Headline value
$50.00
True fair value
$23.81
% of face value
47.6%
At minimum odds of 2.00, a $50 free bet has an expected cash value of about $23.81 — because the stake isn't returned and roughly 50% of free bets lose outright.
Before you place this bet
- • The house always wins. The overround is built into every line offered. These are mathematical facts, not opinions.
- • No betting system, tipster, or strategy can overcome the house edge long-term — that's what "edge" means.
- • "Free bets" and bonuses are marketing. Compute the fair value above before treating them as real cash.
- • Chasing losses is the single strongest predictor of gambling-related harm.
If you or someone you know has a gambling problem:
Simulations use a Bernoulli process with a "true probability" derived from implied probability and an assumed market overround. Exact values depend on bookmaker, sport, and liquidity. The expected-loss direction, however, is mathematical — not subject to opinion.