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Understanding Odds — Implicit Probability and Value Betting
How to calculate implicit probability from odds? Value betting basics.
Bonuszadaz team· May 4, 2026· 1 minute read
Without understanding odds, no one can be a profitable bettor.
Implicit probability
From decimal odds:1 / odds × 100%
- 2.00 = 50%
- 1.50 = 66.7%
- 3.00 = 33.3%
- 5.00 = 20%
Bookmaker margin
The bookmaker calculates all 1X2 odds with the implicit probabilities exceeding 100%. The difference = margin (overround).
E.g. 1: 2.10 (47.6%), X: 3.50 (28.6%), 2: 3.40 (29.4%). Total 105.6% = 5.6% margin.
Value betting
There is value if your own estimate is higher than the implicit probability.
Example
Odds 2.50 (implicit: 40%). You estimate 50%. EV = 0.5 × 1.5 - 0.5 × 1 = +0.25 = +25% value .
Long-term
You are a winner from 1000+ value bets. The outcome of each bet is random, the average counts.
Calculator: Odds Converter .
