What is a value bet?
A bet has value when its odds pay more than the outcome's true probability deserves. Put in one line:
Expected value (EV) = odds × true probability − 1
If the result is above zero, the bet has value. A coin flip at odds of 2.10 is a value bet: the true probability is 50%, so EV = 2.10 × 0.50 − 1 = +5%. Over many such bets you'd expect to win 5% of everything you stake. Any single bet can still lose. For the idea behind it, read what is value betting.
The method in five steps
- 01
Choose a reference market
You can't see the true probability, so you borrow the best estimate there is: the sharpest bookmaker in the market, with low margins, high limits and prices shaped by professional money. See sharp vs soft bookmakers.
- 02
Remove the margin
The reference price includes the bookmaker's fee. Convert prices to probabilities, take out the margin and you get the fair probability and the fair odds. The free no-vig calculator does it for any market.
- 03
Compare on exactly the same line
Look for the same match, market, period and line (for example over/under 2.5 goals, full time) at your bookmaker. A different line is a different bet.
- 04
Calculate the edge
Divide your bookmaker's odds by the fair odds and subtract 1. Many bettors only act above a minimum edge, such as +2% to +3%, to leave room for errors in the fair price.
- 05
Stake with a rule and track it
Use small fixed stakes or a fraction of Kelly, record each bet and judge the method by closing line value, not by last week's profit.
Worked example: a football 1X2 market
The reference bookmaker prices a match at 2.10 (home), 3.40 (draw) and 3.60 (away). The implied probabilities add up to 104.8%, so there's a 4.8% margin in the prices. With the power method the margin comes out like this:
| Outcome | Reference odds | Fair odds | Your bookmaker | Edge |
|---|---|---|---|---|
| Home | 2.10 | 2.173 | 2.30 | +5.8% |
| Draw | 3.40 | 3.597 | 3.30 | −8.3% |
| Away | 3.60 | 3.819 | 3.50 | −8.4% |
Only the home win has value: your bookmaker pays 2.30 and the bet is worth 2.173, so EV = 2.30 ÷ 2.173 − 1 = +5.8%. The draw and the away win are priced below their fair odds: the same bookmaker that's generous on one outcome is stingy on the others. Value is found outcome by outcome, never match by match.
Why the fair price is only an estimate
The reference market is very good, not perfect. Its price can be wrong, it can move after you bet and different ways of removing the margin give slightly different fair odds. That's why a minimum edge helps, and why the real test is whether the prices you take tend to beat the closing fair price. We explain the maths in how BetTheDrop works out fair odds.
How many value bets do you need before you can judge?
More than you'd think. Take bets at odds of 2.00 with a true +5% edge. Each bet swings about ±1 unit, so after 100 bets you expect +5 units but with a spread of roughly ±10: about a 69% chance of being ahead. After 1,000 bets the expected profit is +50 units with a spread of ±32: about 94%. A month of results proves almost nothing; hundreds of bets with positive closing line value prove a lot.
What goes wrong in practice
- Stale prices. The odds you saw may have changed by the time you place the bet. Value that has disappeared is not value.
- The wrong line or period. −0.5 is not −0.75; first half is not full time. Check the exact selection.
- Ignoring limits. A reference price on a market with tiny limits is less reliable than one where large stakes are accepted.
- Typing errors. One wrong digit turns a bad bet into an apparent +20% edge. Be suspicious of edges above 10% on main markets.
- Account restrictions. Bookmakers can limit accounts that consistently take prices better than the market. Many value bettors spread their bets across several bookmakers.
- Small samples. Judging a method after twenty bets.
Where to start
- Main lines first. Moneyline or 1X2, the main handicap and the main total are priced most accurately and have the highest limits.
- Sports you follow. You'll spot typing errors and strange lines faster.
- A few bookmakers you can really use. Three or four accounts with decent limits beat ten with tiny ones.
What to record for every bet
A simple spreadsheet is enough: date, match, market and line, the price you took, the fair price at that moment, your edge, the stake, the closing fair price and the result. The two columns that matter most are the edge when you bet and the closing fair price: together they give your CLV, the only number that tells you early whether the method works.
Finding value faster
Finding value faster
Doing this by hand for every match is slow. The shortcut is to let the market tell you where to look: when the sharp price drops, bookmakers that haven't moved yet are often paying more than the new fair price. That is exactly what BetTheDrop's alerts deliver on Telegram, with the fair price and the value of your price on every message. The free expected value calculator covers any single bet.