PH90 Sports Betting Odds: Converting Any Format Fast
Decimal odds are the total return per unit staked, fractional odds are the profit per unit, and American odds are the profit on 100 or the stake needed to win 100.
Key facts and contents
- Step 1
- Turn everything into decimal first
- Step 2
- Divide 1 by the decimal price
- Step 3
- Add both sides of the market
Three formats are in circulation and they encode exactly the same thing. Learning to move between them takes about five minutes and makes every price on every site directly comparable.
Why sports betting odds come in three shapes
3 formats are in circulation because 3 markets grew up separately, not because they measure different things. A ₱100 stake returns the same amount whichever way the price is written. The sports betting odds below are the same prices written three ways.
The three formats side by side
| Implied chance | Decimal | Fractional | American |
|---|---|---|---|
| 80.0% | 1.25 | 1/4 | -400 |
| 66.7% | 1.50 | 1/2 | -200 |
| 50.0% | 2.00 | 1/1 | +100 |
| 33.3% | 3.00 | 2/1 | +200 |
| 25.0% | 4.00 | 3/1 | +300 |
| 10.0% | 10.00 | 9/1 | +900 |
The pattern worth committing to memory is the middle row. Even money is 2.00, 1/1 and +100, and everything above or below that line is a shading in one direction or the other.
Why decimal wins for reading a market
Decimal is the only format where the implied probability is 1 division away: 1 divided by 2.00 is 50%. Fractional requires adding the stake back before you can divide; American requires a different operation depending on whether the number is positive or negative.
Since reading a sports betting price is to add both sides and find the margin, the format that reaches a probability fastest is the one to work in. Convert first, judge second.
The trap in the negative numbers
American odds catch people out in one specific way. A price of -150 and a price of +150 are not two sides of a fair market — they are 60% and 40%, which sums to 100% exactly and would mean the book was making nothing.
Real two-way American markets look more like -120 / +100 or -110 / -110, and the second of those is the standard: both sides at -110 implies 52.4% each, for a total of 104.8% and a margin of 4.8%. That is the shape a built-in house edge takes in this format, and it is much less obvious than the same margin written as 1.90 / 1.90.
Three-way markets need all three legs
Football markets with a draw are where the arithmetic most often goes wrong, because it is easy to convert two prices and forget the third. A market at 2.10 / 3.40 / 3.60 implies 47.6, 29.4 and 27.8%. Those sum to 104.8%, and the 4.8% is the margin — invisible unless the draw is included.
The same applies to any market with more than two outcomes: a correct-score market with twenty legs carries its margin spread across all twenty, and reading any one of them in isolation tells you nothing about what the market as a whole costs.
Where prices come from
Nothing above says anything about which books offer which prices, or which hold a PAGCOR licence. Who licenses online betting here covers who is licensed to take a bet in this market, which is a separate question from how the price is built.
FAQ
Which format is most common in the Philippines?
Decimal is the default on most sites reaching this market, with fractional appearing on UK-facing products and American on US-facing ones. All three carry identical information, so the choice is presentation rather than substance.
Does a shorter price mean a better bet?
It means a more likely outcome as the book sees it, which is not the same thing. A short price with a fat margin is worse value than a longer price with a thin one, and the only way to tell is to convert both and compare.
Why do fractional odds use awkward numbers like 11/8?
They date from a period when prices were quoted verbally at a racecourse and moved in conventional steps. The steps survived; the reason did not. 11/8 is simply 2.375 in decimal.
What is an even-money bet worth?
Decimal 2.00, fractional 1/1, American +100 — all the same price, all implying exactly 50%. Two of them at once would make a market with no margin at all, which is why you will not see it.