# Implied probability calculator

> Independent. Not affiliated with, endorsed by or sponsored by Novig.

Canonical: https://novigapi.com/implied-probability-calculator
Method checked: 2026-11-12
Interactive tool: https://novigapi.com/implied-probability-calculator (prefill with ?a=&b=)

Implied probability is the chance a price implies: -150 implies 60.00% and +130 implies 43.48%. Together they sum to 103.48%, so the no-vig probabilities are 57.98% and 42.02%. Novig quotes this probability directly as a percentage (Novig docs, checked 12 Nov 2026).

## Worked example

Implied probability by price

| American | Decimal | Implied |
| --- | --- | --- |
| -300 | 1.333 | 75.00% |
| -200 | 1.50 | 66.67% |
| -150 | 1.667 | 60.00% |
| -110 | 1.909 | 52.38% |
| +100 | 2.00 | 50.00% |
| +130 | 2.30 | 43.48% |
| +200 | 3.00 | 33.33% |
| +400 | 5.00 | 20.00% |

```
American < 0: p = -A / (-A + 100)
American > 0: p = 100 / (A + 100)
decimal: p = 1 / D
```

A single price includes the book's margin, so its implied probability overstates the true chance. Enter the other side too and the tool removes the margin with the multiplicative method. For other methods, use the no-vig calculator.

## How to use it

1. Enter a price in any format.
2. Optionally enter the other side of the market.
3. Read the implied and no-vig probabilities.

## Questions

### How do you calculate implied probability from American odds?

For negative odds, divide the odds by the odds plus 100 (ignoring the sign). For positive odds, divide 100 by the odds plus 100.

### What is the implied probability of a Novig price?

The price itself: a 40% contract implies 40%.

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