Fair odds from Matchbook prices
- Commission model
- net winnings
- Rate (placeholder)
- 4%
- Even money after commission
- 1.960
- Lay bets
- yes
- Worst-case probabilities are per-outcome minimums and do not add up to 100%.
| Outcome | Multiplicative | Additive | Powerk = 1.071 | Shinz = 0.047 | Worst case |
|---|---|---|---|---|---|
| Outcome 1 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 |
| Outcome 2 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 |
- Overround
- 4.71%
- Margin
- 4.50%
- Outcomes
- 2
Overround 4.71%
Exchange markets have a much smaller overround than bookmaker markets, because prices are set by traders competing for each other's money rather than by a margin-taking bookmaker. That makes Matchbook prices a good starting point for a fair line. Enter both sides (or every outcome) of a Matchbook market above and the calculator removes what little margin remains with five methods.
Two things to correct for
First, the spread. The back price and the lay price on Matchbook differ, and the fair price sits between them. Devig the back prices for a conservative line, or the midpoint of back and lay for a central one.
Second, commission. A price on Matchbook is worth less than it shows once 4% net winnings comes off; even money becomes 1.960. When you compare a devigged exchange line with a bookmaker price you will actually take, compare after commission on the exchange side. The commission calculator for Matchbook gives the effective odds.
| Odds | Effective | American | Break-even | Net profit on 100 |
|---|---|---|---|---|
| 1.50 | 1.480 | -208 | 67.57% | 48.00 |
| 1.91 | 1.874 | -114 | 53.37% | 87.36 |
| 2.00 | 1.960 | -104 | 51.02% | 96.00 |
| 2.50 | 2.440 | +144 | 40.98% | 144.00 |
| 3.00 | 2.920 | +192 | 34.25% | 192.00 |
| 5.00 | 4.840 | +384 | 20.66% | 384.00 |
| 10.00 | 9.640 | +864 | 10.37% | 864.00 |
Step by step
- Note the back price of every outcome on Matchbook (or the midpoint of back and lay).
- Enter them in the calculator above; the overround and margin appear immediately.
- Choose a method, or keep the comparison view and read the worst-case column.
- Enter the bookmaker price you are offered in the price-check panel and read the edge; apply Matchbook's commission to the exchange side first if you intend to bet there.
Which method
For two-way markets close to even money every method agrees within a few hundredths of a percent. For three-way and multi-way markets, or when there is a long outsider, the power and Shin methods better reflect where bookmakers hide their margin. The worst-case column gives the most conservative probability for a bettor.
Frequently asked questions
Why devig exchange prices at all?
Even trader-set prices carry a small overround, and the back and lay sides differ. Devigging both sides gives one fair probability per outcome to compare against bookmaker prices.
Should I devig the back or the lay prices on Matchbook?
Back prices give a conservative line, lay prices a generous one; the midpoint is a reasonable central estimate. Whichever you choose, apply Matchbook's 4% commission before comparing with a bookmaker.
Which method fits exchange markets best?
For two-way markets near even money the methods agree. For markets with long outsiders, power or Shin better reflect how margin concentrates on the outsiders; the worst-case column is the safest single number.