How to use this betting tool
- Enter the requested assumptions using the units shown.
- Check that probability, odds, stake, line, or outcome values match your intended market.
- Select Calculate, then read the main result and its stated assumption.
#020 · Odds Formats & Market Comparison Tool
American Odds Converter
Convert an American moneyline price into decimal odds, fractional odds and its simple implied probability.
Calculator
Moneyline inputmoneyline
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What this tool calculates
Convert an American moneyline price into decimal odds, fractional odds and its simple implied probability.
For positive A: decimal = 1 + A/100. For negative A: decimal = 1 + 100/|A|. Implied probability = 1/decimal.
Results are informational. Actual limits, deductions, voids and settlement can vary by operator and jurisdiction.
Worked example
American +150 converts to decimal 2.50, fractional 3/2 and an implied probability of 40%. American −200 converts to decimal 1.50.
| Input or result | Value |
|---|---|
| American odds | +150 |
| Decimal odds | 2.50 |
| Implied probability | 40% |
Tips and limitations
- Use estimates from one consistent source and market definition.
- Do not confuse total return with net profit.
- Recalculate if any input or settlement assumption changes.
- Real betting involves loss risk; a calculator cannot remove it.
FAQ
What formula does the American Odds Converter use?
For positive A: decimal = 1 + A/100. For negative A: decimal = 1 + 100/|A|. Implied probability = 1/decimal.
Are the displayed results bookmaker odds or fair estimates?
They are arithmetic results from your inputs. They do not retrieve live prices or add a bookmaker margin.
When does rounding happen?
The calculator keeps full JavaScript numeric precision during calculation and rounds only the displayed values.
Can operator settlement rules change the result?
Yes. Voids, deductions, dead heats, correlated markets and house rules may change real settlement where relevant.
Does this result predict a winning bet?
No. It explains betting mathematics from entered assumptions and does not predict an event or guarantee a return.
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Calculation reference
| Item | Definition |
|---|---|
| Main output | Decimal odds |
| Method | Browser-only arithmetic |
| Live data | Not used |
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