What is value betting?

Value betting means placing bets where the odds offered by the bookmaker imply a lower probability than your own estimate of the true probability. Over a large sample, positive expected value bets generate long-term profit.

How do you calculate expected value on a bet?

EV = (P_win × Profit) − (P_loss × Stake). For example, at odds of 3.00 with a 40% true probability: EV = (0.40 × 200) − (0.60 × 100) = 80 − 60 = +£20 on a £100 bet.

How do you find value bets?

By building a probability model (statistical or informed) and comparing your estimates to implied bookmaker probabilities. Sources of value include public bias, late team news, niche markets, and cross-market inefficiencies.

Value Betting: The Complete Framework

What Is a Value Bet?

A value bet exists when your estimated probability of an outcome is higher than the probability implied by the bookmaker's odds. It has nothing to do with whether the bet wins or loses on any single occasion — it's about whether the price was favourable relative to the true chance of the outcome.

Value exists when: Your True Probability > Bookmaker's Implied Probability

Worked Example

A bookmaker prices a tennis player to win at decimal odds of 2.20 → implied probability of 45.5% (1 ÷ 2.20). Through your own analysis of recent form, surface fit, and head-to-head record, you estimate their true win probability at 55%.

Bookmaker's implied probability: 45.5%
Your estimated probability: 55%
Edge: +9.5 percentage points

This is a value bet — even though the player might still lose this particular match.

Calculating Expected Value (EV)

EV = (Probability of Win × Profit if Win) − (Probability of Loss × Stake)

Using the example above with a $100 stake at 2.20 (profit of $120 if won):

EV = (0.55 × $120) − (0.45 × $100) = $66 − $45 = +$21

A positive EV means that, on average, repeating this exact bet many times would profit $21 per $100 staked — even though individual results vary wildly.

Where Value Actually Comes From

Your own modelling. Statistical models (e.g. Poisson models for football) that estimate probabilities independently of bookmaker pricing.
Information edges. Acting on news (injuries, lineup changes, weather) faster than the market repriced it.
Soft markets. Niche leagues, player props, and smaller bookmakers with less sharp pricing.
Line shopping. The same bet priced differently across bookmakers — see our line shopping guide.

The Hard Truth About Value Betting

Finding genuine value consistently is extremely difficult — it requires either superior modelling, faster information, or access to softer markets than the wider betting public. Most casual bettors who believe they're finding value are actually just experiencing normal variance. The only reliable long-term signal of skill is Closing Line Value (CLV) — consistently beating the final market price before an event starts.

Sizing Your Value Bets

Once you've identified value, the next question is how much to stake. This is where the Kelly Criterion and broader bankroll management principles come in — sizing bets proportionally to your edge protects you from ruin during inevitable losing streaks.

Value Betting — The Core Concept