# Odds converter with implied probability

> Convert betting odds between American, decimal and fractional formats, see implied probability and the margin of a two-outcome market. Formulas and six worked examples.

Source: https://reviewstandings.com/odds-converter/
Updated: 2026-11-13

This converter turns American, decimal or fractional odds into each of the other formats and shows the implied probability, which is 1 divided by the decimal odds. For a two-outcome market it also shows the combined probability and the margin above 100%. It uses only the numbers you enter and carries no operator odds, offers or picks.

## Convert a price

Without scripts, use the formulas and the table below. Both give the same results.

**Formulas · version 1.0 · derived, not sourced from an operator · 2026-11-13**

| From | To decimal (D) | Implied probability |
|---|---|---|
| American A < 0 | D = 1 + 100 / \|A\| | p = 1 / D |
| American A > 0 | D = 1 + A / 100 | p = 1 / D |
| Fractional n/d | D = 1 + n / d | p = d / (n + d) |

## Six worked examples

**Example (not an offer) · hypothetical prices · derived values · 2026-11-13**

| American | Decimal | Fractional | Implied probability |
|---|---|---|---|
| -110 | 1.9091 | 10/11 | 52.38% |
| +100 | 2.0000 | 1/1 | 50.00% |
| +150 | 2.5000 | 3/2 | 40.00% |
| -200 | 1.5000 | 1/2 | 66.67% |
| +130 | 2.3000 | 13/10 | 43.48% |
| -150 | 1.6667 | 2/3 | 60.00% |

**Takeaway:** a shorter price means a higher implied probability, and the formulas are the same on every page of this site.

## Two outcomes and the margin

Add the two implied probabilities. The amount over 100% is the margin. Dividing each probability by the sum gives the no-margin split.

**Example (not an offer) · two-outcome markets · derived · 2026-11-13**

| Prices | Sum of probabilities | Margin | Split without margin |
|---|---|---|---|
| -110 / -110 | 104.76% | 4.76 points | 50.00% / 50.00% |
| -150 / +130 | 103.48% | 3.48 points | 57.98% / 42.02% |

Terms: [implied probability](https://reviewstandings.com/what-is-implied-probability/) and [vig](https://reviewstandings.com/what-is-vig/).

## When the result is wrong

- **Typed the wrong sign.** -110 and +110 are different prices; see [what a moneyline is](https://reviewstandings.com/what-is-a-moneyline/).
- **Three or more outcomes.** The margin formula above is for two outcomes. For more outcomes, add all probabilities.
- **Reading the result.** An implied probability is a price, not a forecast; see [what implied probability means](https://reviewstandings.com/what-is-implied-probability/).
- **Rounding.** Results are rounded; an operator's printed price can differ in the last digit.

We have no operator odds, so we cannot say whose price is higher. Gambling involves risk. Play responsibly.

## How we checked

1. We recomputed each row by hand from the formulas.
2. We checked that the converter and this table agree.
3. We kept operator odds out of the page.

## Sources

- Formulas are standard arithmetic, version 1.0, dated 2026-11-13; they are derived values, not operator data.

## What changed

- 2026-11-13: first version.

## FAQ

**What does an implied probability of 52.38% mean?**

It is the chance that the price alone suggests: 1 divided by the decimal odds. American -110 equals decimal 1.9091, so 1 / 1.9091 = 52.38%. It is not a forecast of the game.

**Why do two sides at -110 add up to more than 100%?**

Each side is 52.38%, so the pair adds to 104.76%. The 4.76 points above 100 are the margin built into the price.

**Does this converter show real odds from sportsbooks?**

No. It converts numbers you type. It carries no operator odds, and the examples below are marked as examples.

**Why is a result rounded?**

The converter rounds decimal odds to four places and probabilities to two decimals. A fractional result is shown as the nearest simple fraction, so it can differ slightly from a price an operator prints.