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+320 Odds Explained

Decimal
4.20
American
+320
Fractional
16/5
Implied probability
23.81%
Polymarket
24¢
$100 wins
320.00
Inputs
Results
Decimal odds4.200
American
+320
Fractional
16/5
Implied probability
23.81%
Polymarket
24¢
Profit
320.00
Total return
420.00

4.200 decimal, +320 American, 23.81% implied probability

+320 is an American price:

the plus sign marks an underdog, and the number is the profit on a 100 stake

. Every other format describes the same chance: 4.20 decimal, 16/5 fractional, 23.81% implied probability, 24¢ on Polymarket.

What +320 pays

A 100 stake at +320 returns 420.00 in total: your 100 back plus 320.00 profit. To win exactly 100 you would stake 31.25. The table covers the stakes people actually use.

Payout by stake
StakeProfitTotal return
1032.0042.00
2580.00105.00
50160.00210.00
100320.00420.00
5001,600.002,100.00
1,0003,200.004,200.00

Break-even and long-run results

The implied probability of +320 is 23.81%, and that number is also the break-even win rate: win more often than 23.81% of the time at this price and you profit in the long run, win less often and you lose. The table shows the return on stake at a few win rates, including the break-even rate itself.

Return on stake by long-run win rate
Win rateReturn on stake
24%0.8%
50%110.0%
55%131.0%
60%152.0%
65%173.0%

+320 is a longshot. The bookmaker prices the outcome at 23.81%, and the payout of 320.00 per 100 staked is the compensation for how rarely it lands. Longshots carry more margin than any other part of the market, which is why devigging methods disagree most at prices like this one.

The vig at +320

If both sides of a two-way market were priced at +320, the implied probabilities would add up to -52.38% above 100%. That excess is the overround, or vig; as a share of stakes it is a -110.00% margin for the bookmaker. Removing it leaves fair odds of 2.00 decimal ( +100) on each side. Use the devig calculator to do the same for any market.

+320 on a betting exchange

Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission +320 is worth 4.136 decimal (+314 American); at 5% it drops to 4.040 (+304). Those are the bookmaker prices you would need to beat.

Effective odds on an exchange
CommissionEffective decimalEffective AmericanBreak-even
2%4.136+31424.18%
5%4.040+30424.75%

Same price in other formats

Same price in other formats

Nearby prices

Nearby prices

  • +310 · 4.10 · 24.4%
  • +315 · 4.15 · 24.1%
  • +318 · 4.18 · 23.9%
  • +319 · 4.19 · 23.9%
  • +321 · 4.21 · 23.8%
  • +322 · 4.22 · 23.7%
  • +325 · 4.25 · 23.5%
  • +330 · 4.30 · 23.3%

Frequently asked questions

What does +320 mean in betting?

+320 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At +320 the implied probability is 23.81% and a 100 stake returns 420.00.

What is +320 in decimal odds?

+320 converts to 4.200 in decimal odds (usually shown as 4.20). Decimal odds are the total return per unit staked, so multiply your stake by 4.200 to get the return.

What is +320 as a fraction?

+320 is 16/5 in fractional odds, the traditional bookmaker notation where the top number is profit and the bottom number is stake.

How much do I win on a 100 bet at +320?

A 100 stake at +320 wins 320.00 in profit and returns 420.00 including the stake. To win exactly 100 you would stake 31.25.

What win rate do I need at +320?

The break-even win rate equals the implied probability, 23.81%. Winning more often than that at this price is profitable over the long run; winning less often loses money.