Jili9 Sportsbook Odds — Converting a Price Step by Step
Sports betting odds convert to an implied probability with one formula: 1 divided by the decimal price.
Key facts and contents
- Step 1
- Identify the decimal price quoted for the outcome
- Step 2
- Divide 1 by the decimal price
- Step 3
- Repeat for every outcome in the market and add the results
- Step 4
- Subtract 100% from the total to find the overround
Sportsbook odds convert to an implied probability with one formula, and the same formula finds a market’s overround once every outcome has been converted. This page works the conversion step by step, then lays out decimal, fractional and American formats side by side so a price quoted in any of the three can be read the same way.
What Sportsbook Odds Actually State
A decimal price of 1.90 states that a winning ₱100 stake returns ₱190 in total — the ₱100 stake plus ₱90 in profit. The same price converts directly to an implied probability with the formula used throughout this page: 1 divided by the decimal price.
| Decimal price | Return on ₱100 | Implied probability |
|---|---|---|
| 1.50 | ₱150 | 66.7% |
| 1.90 | ₱190 | 52.6% |
| 3.00 | ₱300 | 33.3% |
| 5.00 | ₱500 | 20.0% |
Converting Decimal Odds to Implied Probability
The formula is 1 ÷ decimal price. For a price of 1.90, that is 1 ÷ 1.90 = 0.526, or 52.6%. For a price of 3.00, it is 1 ÷ 3.00 = 0.333, or 33.3%. A shorter price always converts to a higher implied probability, and a longer price always converts to a lower one.
Finding the Overround
Add the implied probability of every outcome in a market together. A two-way market priced 1.90 on each side converts to 52.6% + 52.6% = 105.3%. The 5.3 percentage points over 100% is the overround — the sportsbook’s margin on that market, expressed in the same units as the probabilities themselves.
The Step-By-Step Conversion
- Identify the decimal price quoted for the outcome.
- Divide 1 by the decimal price to get its implied probability.
- Repeat for every outcome in the market and add the percentages together.
- Subtract 100% from that sum to find the overround in percentage points.
Decimal, Fractional and American, Side by Side
| Decimal | Fractional | American | Implied probability |
|---|---|---|---|
| 1.50 | 1/2 | −200 | 66.7% |
| 1.90 | 9/10 | −111 | 52.6% |
| 2.00 | 1/1 | +100 | 50.0% |
| 3.00 | 2/1 | +200 | 33.3% |
| 5.00 | 4/1 | +400 | 20.0% |
Fractional odds state profit relative to stake — 9/10 means ₱9 profit for every ₱10 staked, which is the same price as decimal 1.90. American odds flip sign at even money: a negative number states how much must be staked to profit ₱100, and a positive number states how much profit a ₱100 stake returns.
Reading a Line at Jili9
- Open the odds board for the match in Jili9’s sportsbook section.
- Note the decimal price shown for each outcome, converting from fractional or American first if that is the format displayed.
- Run the four-step conversion above to find the market’s own overround before deciding how the price compares to a fair one.
The sportsbook betting pillar page carries the full pricing mechanism this procedure is drawn from, including how margins compound across a multi-leg bet, and the esports betting settlement rules page applies the same overround math to markets that settle on a single map. The turnover meaning page covers how that figure is measured regardless of which sportsbook market produced the stake, which is worth reading before combining several priced legs into one bet.
FAQ
How do you convert sports betting odds to a percentage?
Divide 1 by the decimal price and multiply by 100. A price of 1.90 gives 1 ÷ 1.90 = 0.526, or 52.6%. The same formula works on any decimal price, whatever sport or market it comes from.
What is the overround in sports betting odds?
It is the amount by which a market's added-up implied probabilities exceed 100%. A two-way market summing to 105.3% carries a 5.3 percentage point overround, which is the margin built into that market.
How do American odds convert to decimal?
A negative American price converts with 1 + (100 ÷ the number without its minus sign); a positive American price converts with 1 + (the number ÷ 100). −111 converts to 1 + (100 ÷ 111) = 1.90, and +190 converts to 1 + (190 ÷ 100) = 2.90.
Why doesn't a fair coin-flip market price at exactly 2.00 on each side?
Because a sportsbook builds its margin into the price rather than quoting a true 50/50 chance at 2.00. Pricing each side at 1.90 instead of 2.00 is what produces the 105.3% overround shown in the worked example above.