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4.05 Decimal Odds Explained

Decimal
4.05
American
+305
Fractional
61/20
Implied probability
24.69%
Polymarket
25¢
$100 wins
305.00
Inputs
Results
Decimal odds4.050
American
+305
Fractional
61/20
Implied probability
24.69%
Polymarket
25¢
Profit
305.00
Total return
405.00

4.050 decimal, +305 American, 24.69% implied probability

Decimal odds of 4.05 return 4.05 for every 1.00 staked, stake included, so the profit on a unit is 4.05 minus one. The same price is +305 in American notation and 61/20 as a fraction, and it implies an implied chance of 24.69% of winning.

What 4.05 pays

Multiply the stake by 4.05 to get the total return. A 100 stake returns 405.00, of which 305.00 is profit. To win 100 in profit you would need to stake 32.79.

Payout by stake
StakeProfitTotal return
1030.5040.50
2576.25101.25
50152.50202.50
100305.00405.00
5001,525.002,025.00
1,0003,050.004,050.00

Break-even and long-run results

One divided by 4.05 is 24.69%: 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
25%1.2%
50%102.5%
55%122.8%
60%143.0%
65%163.2%

4.05 is a longshot price implying 24.69%. Bookmakers shade longshots more than any other price, so the true chance is usually a little higher than the implied figure suggests; the power and Shin devigging methods exist largely to model that shading.

Converting 4.05 by hand

Every other format follows from the decimal price in one step. Implied probability is one divided by 4.05, which gives 24.69%. American odds depend on which side of 2.00 the price sits: at or above 2.00, multiply (4.05 − 1) by 100 to get +305. The fraction is 4.05 − 1 written as a ratio and snapped to the nearest traditional price, 61/20. A prediction market simply quotes the probability in cents: 25¢.

The vig at 4.05

If both sides of a two-way market were 4.05, their implied probabilities would sum to -50.62% above 100%. That is the overround; as a share of stakes it is a -102.50% 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.

4.05 on a betting exchange

Exchange commission comes off winnings, so 4.05 at 2% commission is really 3.989, and at 5% it is 3.898. The break-even win rate rises accordingly.

Effective odds on an exchange
CommissionEffective decimalEffective AmericanBreak-even
2%3.989+29925.07%
5%3.898+29025.66%

Same price in other formats

Same price in other formats

Nearby prices

Nearby prices

  • 3.80 · 3.80 · 26.3%
  • 3.95 · 3.95 · 25.3%
  • 4.00 · 4.00 · 25.0%
  • 4.10 · 4.10 · 24.4%
  • 4.15 · 4.15 · 24.1%
  • 4.30 · 4.30 · 23.3%

Frequently asked questions

What does 4.05 decimal odds mean?

Decimal odds of 4.05 return 4.05 for every 1.00 staked, including the stake, so the profit is 4.05 minus 1. The implied probability is 24.69%.

What is 4.05 in American odds?

4.05 decimal is +305 in American odds. Prices of 2.00 and above convert with (decimal − 1) × 100; prices below 2.00 with −100 / (decimal − 1).

What is 4.05 as a fraction?

4.05 is 61/20 in fractional odds: subtract 1 from the decimal price and express the result as a fraction.

How much does 100 return at 4.05?

100 × 4.05 = 405.00 total return, of which 305.00 is profit.

What win rate breaks even at 4.05?

1 / 4.05 = 24.69%. 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.