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2/9 Fractional Odds Explained

Decimal
1.22
American
-450
Fractional
2/9
Implied probability
81.82%
Polymarket
82¢
$100 wins
22.22
Inputs
Results
Decimal odds1.222
American
-450
Fractional
2/9
Implied probability
81.82%
Polymarket
82¢
Profit
22.22
Total return
122.22

1.222 decimal, -450 American, 81.82% implied probability

Fractional odds of 2/9 pay 22.22 profit on a 100 stake: the top number is the profit, the bottom number the stake. In decimal notation the price is 1.22, in American notation -450, and the implied probability is 81.82%.

What 2/9 pays

Profit is stake multiplied by the fraction; add the stake back for the total return. A 100 stake wins 22.22 and returns 122.22.

Payout by stake
StakeProfitTotal return
102.2212.22
255.5630.56
5011.1161.11
10022.22122.22
500111.11611.11
1,000222.221,222.22

Break-even and long-run results

The implied probability of 2/9 is bottom divided by top-plus-bottom, which is 81.82%. Win more often than that and you profit over time.

Return on stake by long-run win rate
Win rateReturn on stake
50%-38.9%
55%-32.8%
60%-26.7%
65%-20.6%
82%0.2%

2/9 is odds-on and short: the implied probability is 81.82%. Fractional prices below 1/3 are where the risk of a run of small wins being undone by a single loss is highest.

Converting 2/9 by hand

Divide the top of the fraction by the bottom and add one for the decimal price, 1.22. For the implied probability, divide the bottom by the sum of top and bottom: 81.82%. American odds follow from the decimal price: odds-on, so −100 divided by (1.22 − 1) gives -450. The same chance on a prediction market is a 82¢ share.

The vig at 2/9

With both sides of a two-way market at 2/9, implied probabilities would sum to 63.64% above 100%: a 38.89% margin on stakes. The fair price would be 2.00 decimal each side. Try other markets in the devig calculator.

2/9 on a betting exchange

On an exchange 2/9 is worth 1.218 decimal after 2% commission and 1.211 after 5%. Compare with the bookmaker before choosing where to bet.

Effective odds on an exchange
CommissionEffective decimalEffective AmericanBreak-even
2%1.218-45982.12%
5%1.211-47482.57%

Neighbouring rungs on the ladder

Fractional prices move in fixed rungs rather than smooth steps, so a bookmaker who wants to shorten 2/9 slightly has to jump to the next rung down, and the size of that jump depends on where you are on the ladder. The nearby prices listed below are the rungs on either side of 2/9; each link opens the same set of facts for that price, which is the quickest way to see how much a one-rung move changes the implied probability and the payout.

Same price in other formats

Same price in other formats

Nearby prices

Nearby prices

  • 1/6 · 1.17 · 85.7%
  • 2/11 · 1.18 · 84.6%
  • 1/5 · 1.20 · 83.3%
  • 1/4 · 1.25 · 80.0%
  • 2/7 · 1.29 · 77.8%
  • 3/10 · 1.30 · 76.9%

Frequently asked questions

What does 2/9 mean in betting?

Fractional odds of 2/9 pay the top number in profit for every bottom number staked. A 100 stake wins 22.22 and returns 122.22. The implied probability is 81.82%.

What is 2/9 in decimal odds?

2/9 is 1.22 in decimal odds: divide the top by the bottom and add 1.

What is 2/9 in American odds?

2/9 converts to -450 in American odds.

Is 2/9 a good price?

A price is good only relative to the true chance. 2/9 implies 81.82%; if you believe the outcome is more likely than that, the price has value. Compare it with a devigged market to check.

Why do bookmakers use a ladder of fractions?

Tradition and readability: prices such as 6/4, 100/30 and 11/10 are quoted instead of their reduced forms because they are what racecourse bookmakers have always used. Decimal odds show the same prices with finer steps.