How to use this betting tool
- Enter values in the units shown beside each field.
- Choose a settlement option when one is provided.
- Select Calculate and review both the headline and supporting figures.
- Reset before checking a separate scenario.
#151 · Odds Probability & Margin Tool
Favorite and Underdog Probability Calculator
Compare two decimal prices, identify the market favorite, and remove the two-way overround with proportional normalization.
Calculator
Enter the settlement inputsdecimal
decimal
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Formula and calculation
Compare two decimal prices, identify the market favorite, and remove the two-way overround with proportional normalization.
Raw implied probability = 100 ÷ decimal odds. Fair probability = raw probability ÷ the sum of both raw probabilities.
Values are informational. Operator rules, limits, voids and rounding may change an official settlement.
Worked example
At 1.70 and 2.25, the raw probabilities total about 103.27%. Proportional normalization assigns about 56.95% to the favorite and 43.05% to the underdog.
| Check | Meaning |
|---|---|
| Inputs | Use one consistent currency and decimal odds. |
| Output | Review the exact settlement label, not color alone. |
Assumptions and limits
- No live odds or account data is requested.
- Decimal odds must be greater than 1.00.
- Intermediate values are not rounded before the result is displayed.
- This tool does not guarantee profit or recommend a wager.
FAQ
Does this favorite and underdog probability calculator predict an outcome?
No. It performs transparent arithmetic on the values you enter and does not use live data or predict an event.
Why can operator settlement differ?
House rules can define voids, pushes, commissions, promotion eligibility, and rounding differently. Check the rules attached to the wager.
When does the calculator round values?
Calculations retain JavaScript numeric precision and displayed money is rounded to two decimal places only at the output stage.
Can I use American or fractional odds directly?
No. This page expects decimal odds where an odds field appears. Convert other formats before entering them.
Are the results stored or transmitted?
No. The calculation runs locally in your browser and the page does not upload the values you enter.
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Input reference
| Item | Rule |
|---|---|
| Odds | Decimal and greater than 1.00 |
| Money | Non-negative in one currency |
| Precision | Round only for display |