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125/1 Fractional Odds Explained

Decimal
126.00
American
+12,500
Fractional
125/1
Implied probability
0.79%
Polymarket
1¢
$100 wins
12,500.00
Inputs
Results
Decimal odds126.000
American
+12,500
Fractional
125/1
Implied probability
0.79%
Polymarket
1¢
Profit
12,500.00
Total return
12,600.00

126.000 decimal, +12,500 American, 0.79% implied probability

Fractional odds of 125/1 pay 12,500.00 profit on a 100 stake: the top number is the profit, the bottom number the stake. In decimal notation the price is 126.00, in American notation +12,500, and the implied probability is 0.79%.

What 125/1 pays

Profit is stake multiplied by the fraction; add the stake back for the total return. A 100 stake wins 12,500.00 and returns 12,600.00.

Payout by stake
StakeProfitTotal return
101,250.001,260.00
253,125.003,150.00
506,250.006,300.00
10012,500.0012,600.00
50062,500.0063,000.00
1,000125,000.00126,000.00

Break-even and long-run results

The implied probability of 125/1 is bottom divided by top-plus-bottom, which is 0.79%. Win more often than that and you profit over time.

Return on stake by long-run win rate
Win rateReturn on stake
1%26.0%
50%6,200.0%
55%6,830.0%
60%7,460.0%
65%8,090.0%

125/1 is a longshot implying 0.79%. Long fractional prices move in big steps (16/1, 20/1, 25/1, 33/1), and bookmakers shade them heavily, so the fair price is usually longer than the quoted one suggests.

Converting 125/1 by hand

Divide the top of the fraction by the bottom and add one for the decimal price, 126.00. For the implied probability, divide the bottom by the sum of top and bottom: 0.79%. American odds follow from the decimal price: odds-against, so (126.00 − 1) × 100 gives +12,500. The same chance on a prediction market is a 1¢ share.

The vig at 125/1

With both sides of a two-way market at 125/1, implied probabilities would sum to -98.41% above 100%: a -6,200.00% margin on stakes. The fair price would be 2.00 decimal each side. Try other markets in the devig calculator.

125/1 on a betting exchange

On an exchange 125/1 is worth 123.500 decimal after 2% commission and 119.750 after 5%. Compare with the bookmaker before choosing where to bet.

Effective odds on an exchange
CommissionEffective decimalEffective AmericanBreak-even
2%123.500+12,2500.81%
5%119.750+11,8750.84%

Neighbouring rungs on the ladder

Fractional prices move in fixed rungs rather than smooth steps, so a bookmaker who wants to shorten 125/1 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 125/1; 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

Nearby prices

Nearby prices

Frequently asked questions

What does 125/1 mean in betting?

Fractional odds of 125/1 pay the top number in profit for every bottom number staked. A 100 stake wins 12,500.00 and returns 12,600.00. The implied probability is 0.79%.

What is 125/1 in decimal odds?

125/1 is 126.00 in decimal odds: divide the top by the bottom and add 1.

What is 125/1 in American odds?

125/1 converts to +12,500 in American odds.

Is 125/1 a good price?

A price is good only relative to the true chance. 125/1 implies 0.79%; 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.