Skip to content
Browse guides
← All guides
Matched bettingMatched betting basicsBack and lay bettingExchanges and liabilityComplete your first offerUnderstanding 2Up alerts
Value bettingValue betting basicsExpected value and fair oddsProbability and priceVariance and losing runsBankroll and stakingReading a value alert
ArbitrageArbitrage basicsArbitrage checks and availabilityComparing betting prices
Accounts and limitsAccount health and restrictionsLimits, gubbings and account closuresExchanges and sportsbook limitsGood account practice
Using ProfitPandaHow ProfitPanda worksFind your way around DiscordPrepare an exchange accountYour first offer: start hereUsing the OddsMatcherRecord your first betTracking and performanceUnderstanding your performance
Help and referenceWelcome to ProfitPandaBetting glossarySupport and safer gamblingFrequently asked questions
Value betting·2 min read

Expected value and fair odds

Expected value, or EV, tells you the average profit or loss you'd expect over lots of similar bets—if your estimate of the chance is right.

The maths

For a cash back bet with no fees:

EV per £1 = estimated probability × decimal odds − 1. Multiply by 100 for a percentage. Fair odds = 1 ÷ estimated probability.

A 50% chance means fair odds of 2.00. If you get 2.10, the calculation is 0.50 × 2.10 − 1 = +5% EV. On a £10 stake, that's 50p of expected profit on average.

The odds make the difference

Available oddsEstimated chanceEstimated EV
2.1050%+5%
2.0050%0%
1.9050%−5%

If a card shows 2.10 but your betslip shows 1.90, the original edge is gone. Recheck the price rather than using the old percentage.

The estimate can be wrong

Bookies build a margin into their odds. Dividing 1 by one bookie's price doesn't reveal the true chance. Reference prices move too, and fees need to come out of your result.

If the chance in this example were 45% instead of 50%, odds of 2.10 would give −5.5% EV. The estimate matters as much as the price.

Next: Probability and price.