Fundamentals
How to read decimal and American betting odds
Odds express the payout for a successful selection under the market's conditions. They may be decimal, such as 1.80, or American, such as −125. Understanding the format helps you distinguish profit from total return and read a pick in context.
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How decimal odds work
Winning single bet
Total return = stake × odds
Net profit = stake × (odds − 1). This example excludes fees and other costs.
With a hypothetical stake of 10 at odds of 1.80, the total return would be 18. Of that amount, ten is the original stake and eight is profit. If the selection loses, the stake is lost. If it is void with a full stake refund, there is no profit.
Odds of 2.00 mean a successful selection returns twice the stake. They do not necessarily mean the event has an actual 50% chance of happening: odds are an offered price, not an infallible measurement.
What +150 and −150 mean
Positive American odds show the profit for every 100 staked: +150 means a profit of 150 if a selection with a stake of 100 wins. Negative odds show the stake associated with a profit of 100: −150 means a stake of 150 would produce 100 profit on a win.
The base of 100 is a convention of the format. You do not have to stake that amount. Examples can be scaled proportionally to understand the relationship.
Odds conversion examples
| American | Decimal | Profit on a winning 1u pick |
|---|---|---|
| −200 | 1.50 | +0.50u |
| −125 | 1.80 | +0.80u |
| +100 | 2.00 | +1.00u |
| +150 | 2.50 | +1.50u |
| +200 | 3.00 | +2.00u |
Convert American odds to decimal
Positive: 1 + odds / 100
For negative American odds: 1 + 100 / absolute value of the odds.
Both formats describe the same price when converted correctly. Rounding can produce small display differences, particularly if a value is converted back and forth between formats.
What is implied probability?
Implied probability from decimal odds
100 ÷ decimal odds
At odds of 2.00: 50%. At odds of 1.80: approximately 55.56%.
This converts a price into a percentage; it does not establish the event's actual probability. Bookmaker markets can include a margin. For example, two mutually exclusive outcomes at 1.90 each imply about 52.63% apiece. Together they add up to 105.26%, not 100%.
An analyst's probability estimate is not a certainty either. Keep the market price, the analyst's estimate and the eventual outcome clearly separate.
Why the time the odds were published matters
A pick published at 2.10 may be priced at 1.85 when you read it. Even though the selection is the same, the potential return is different. A useful record therefore identifies both the odds and their timing.
Two people's outcomes may differ because of their available prices and stakes. Someone else's result screenshot cannot automatically reconstruct what your own result would have been.
How to read odds on Tipsterline
Tipsterline calculates profit using the odds recorded in the pick. When managing a parlay, the app recalculates its odds if selections are voided. The tipster marks results on that screen; they do not enter new odds. Average odds include only won and lost picks in the selected period.
Read the price together with stake, win rate and profit to understand the record. No odds make a sports outcome certain.
Sources and methodology
Educational content for adults aged 18 and over. Examples are hypothetical. Past results do not guarantee future outcomes. Responsible gambling.
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