Worst line vs best line: what line shopping is worth
Worst line vs best line calculator
Example Our example: −115 at one book, −105 at another.
Win rate 53.2%51.2% no-vig + 2.0% edge
about $2,200 left on the table over 500 bets of $100
- Wins at −115
- $86.96
- Wins at −105
- $95.24
- Your win rate
- 53.2%
- Extra per win
- $8.28
- Tax per bet
- $4.40
- Over 500 bets
- $2,201.26
At a 53.2% win rate the bet expects +$3.79 a bet at −105 but −$0.61 at −115: the worse number turns a winning bet into a losing one.
Show the numbers
| Bets | At −115 | At −105 | Extra juice | Likely range at −105 |
|---|---|---|---|---|
| 0 | $0 | $0 | $0 | $0 to $0 |
| 50 | −$31 | +$189 | $220 | −$499 to +$878 |
| 100 | −$61 | +$379 | $440 | −$595 to +$1,353 |
| 150 | −$92 | +$568 | $660 | −$625 to +$1,762 |
| 200 | −$123 | +$758 | $881 | −$620 to +$2,136 |
| 250 | −$153 | +$947 | $1,101 | −$593 to +$2,488 |
| 300 | −$184 | +$1,137 | $1,321 | −$551 to +$2,824 |
| 350 | −$215 | +$1,326 | $1,541 | −$496 to +$3,149 |
| 400 | −$245 | +$1,516 | $1,761 | −$433 to +$3,464 |
| 450 | −$276 | +$1,705 | $1,981 | −$361 to +$3,772 |
| 500 | −$307 | +$1,895 | $2,201 | −$284 to +$4,073 |
The biggest gaps on the board right now
The same bet, priced by two real books. The calculator above scrolls through these; pick one to show it there.
Lines from the board load here in your browser.
The math
payout = stake × (decimal odds − 1) · −115 → $86.96 on $100 · −105 → $95.24
extra juice per bet = win rate × (best payout − worst payout) · win rate = no-vig win rate + your edge
no edge: 51.2% × ($95.24 − $86.96) = $4.24 a bet · × 500 bets ≈ $2,120
a 2-point edge: 53.2% × $8.28 = $4.40 a bet · × 500 bets ≈ $2,200
The win rate starts from the market’s no-vig price, not 50%. In the example the worst book’s market is −115 / −105; with the vig removed (power method) the −115 side wins 51.2% of the time. The edge box adds your own edge on top, 2 points to start. At 0 the bet is break-even before the vig and both lines on the chart fall; with an edge the best price can make money while the worst price gives it back.
What it is not
The gap is not profit. It is the tax paid for taking the worse number. A bad side is still a bad side at the best price, and the chart shows it: when both lines head down, the best price only loses more slowly. Line shopping is the cheapest edge in betting because it costs nothing but a comparison, not because it makes any bet good. To check whether a price is worth betting at all, compare it to the no-vig price with the EV calculator.
Every game on vigged shows each book’s price with the best value on each side marked (sometimes on a better number), and each game page shows the gap between the worst and best book on every market. Read more in the line shopping guide or see how no-vig odds work. When the books differ on the number rather than the price, the half point calculator prices the difference.
How it works
Hold the stake still and compare what the worst price and the best price on the board pay. The difference only lands on the bets that win, so the extra juice per bet is the win probability times the payout gap. Until the board’s lines load, the calculator shows our own example: −115 at one book, −105 at another.
Frequently asked questions
How much is line shopping worth?
Take the same bet at the worst price on the board and at the best one. The difference in what each pays is only collected when the bet wins, so the cost per bet is the win probability times the payout gap. At −115 against −105 on a $100 bet that is about $4.24 a bet, or about $2,120 over 500 bets.
Why not just use 50% as the win rate?
Because favorites win more often, and the gap is paid on every win. A −300 favorite wins about 75% of the time, so the gap between two prices on it costs half as much again as a coin flip would suggest. The calculator uses the market’s no-vig price probability.
Is the gap profit?
No. It is extra juice: the tax for taking the worse number. A bet that is bad at the worst price is usually still bad at the best price, just less so. Shopping stops you overpaying; it does not turn a losing bet into a winning one.
Where does the win rate come from?
From the market itself, with the vig removed. Enter both prices from the book with the worse number and the calculator de-vigs them with the power method, the same math as the no-vig calculator. Prices loaded from the live board use vigged’s no-vig price for that side. You can override it at any time and reset it back.
Why does the chart have a band?
Because results swing far more than the gap. The two lines are expected results; about two runs in three at the best price finish inside the band. The gap between the lines is steady (you pay it on every bet), but any one stretch of bets can land well above or below either line.
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