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3.15 Decimal Odds Explained

Decimal
3.15
American
+215
Fractional
43/20
Implied probability
31.75%
Polymarket
32¢
$100 wins
215.00
Inputs
Results
Decimal odds3.150
American
+215
Fractional
43/20
Implied probability
31.75%
Polymarket
32¢
Profit
215.00
Total return
315.00

3.150 decimal, +215 American, 31.75% implied probability

3.15 is the decimal way of writing a price that Americans call +215 and British bookmakers call 43/20. Decimal odds are the easiest to compute with: multiply the stake by 3.15 for the total return, and divide one by 3.15 for the implied probability of 31.75%.

What 3.15 pays

Multiply the stake by 3.15 to get the total return. A 100 stake returns 315.00, of which 215.00 is profit. To win 100 in profit you would need to stake 46.51.

Payout by stake
StakeProfitTotal return
1021.5031.50
2553.7578.75
50107.50157.50
100215.00315.00
5001,075.001,575.00
1,0002,150.003,150.00

Break-even and long-run results

One divided by 3.15 is 31.75%: the implied probability, and the win rate at which betting this price neither makes nor loses money. The rows below show the return on stake at several win rates.

Return on stake by long-run win rate
Win rateReturn on stake
32%0.8%
50%57.5%
55%73.3%
60%89.0%
65%104.8%

At 3.15 the implied chance is 31.75%, a moderate underdog. Each win pays 215.00 per 100, and wins come less than half the time by the bookmaker's estimate. Compare prices across several books at this level: outsiders are where they disagree most.

Converting 3.15 by hand

Every other format follows from the decimal price in one step. Implied probability is one divided by 3.15, which gives 31.75%. American odds depend on which side of 2.00 the price sits: at or above 2.00, multiply (3.15 − 1) by 100 to get +215. The fraction is 3.15 − 1 written as a ratio and snapped to the nearest traditional price, 43/20. A prediction market simply quotes the probability in cents: 32¢.

The vig at 3.15

If both sides of a two-way market were 3.15, their implied probabilities would sum to -36.51% above 100%. That is the overround; as a share of stakes it is a -57.50% margin. The fair price with the margin removed is 2.00 on each side. The devig calculator does this for any market and any method.

3.15 on a betting exchange

Exchange commission comes off winnings, so 3.15 at 2% commission is really 3.107, and at 5% it is 3.043. The break-even win rate rises accordingly.

Effective odds on an exchange
CommissionEffective decimalEffective AmericanBreak-even
2%3.107+21132.19%
5%3.043+20432.87%

Same price in other formats

Same price in other formats

Nearby prices

Nearby prices

  • 2.90 · 2.90 · 34.5%
  • 3.05 · 3.05 · 32.8%
  • 3.10 · 3.10 · 32.3%
  • 3.20 · 3.20 · 31.3%
  • 3.25 · 3.25 · 30.8%
  • 3.40 · 3.40 · 29.4%

Frequently asked questions

What does 3.15 decimal odds mean?

Decimal odds of 3.15 return 3.15 for every 1.00 staked, including the stake, so the profit is 3.15 minus 1. The implied probability is 31.75%.

What is 3.15 in American odds?

3.15 decimal is +215 in American odds. Prices of 2.00 and above convert with (decimal − 1) × 100; prices below 2.00 with −100 / (decimal − 1).

What is 3.15 as a fraction?

3.15 is 43/20 in fractional odds: subtract 1 from the decimal price and express the result as a fraction.

How much does 100 return at 3.15?

100 × 3.15 = 315.00 total return, of which 215.00 is profit.

What win rate breaks even at 3.15?

1 / 3.15 = 31.75%. Win more often than that and the price is profitable; the bookmaker's margin means both sides of a market usually sit a little under fair.