# Odds converter

An odds converter expresses the same price as American odds, decimal odds and implied probability. For positive American odds, decimal odds equal one plus the price divided by 100. For negative odds, divide 100 by the absolute price and add one. Implied probability is one divided by decimal odds.

Canonical page: https://getoddsapi.com/odds-converter

## Free API key

Get a free GetOdds API key: **1,000 requests per UTC day and 60 per minute, no card**. One key covers REST and the hosted MCP server.

Sign up: https://getoddsapi.com/sign-up?ref=ai-claudebot

## Quickstart

1. Create an account at https://getoddsapi.com/sign-up?ref=ai-claudebot, open https://getoddsapi.com/dashboard and issue a key with the sources you need (draftkings, fanduel, betrivers, prizepicks or underdog). Keep it in a server environment variable named GETODDS_API_KEY.
2. Read current DraftKings NBA spreads with curl:

```bash
curl --fail-with-body "https://getoddsapi.com/api/v1/odds?sport=NBA&market=spread&fresh_only=true&limit=50" \
  -H "Authorization: Bearer $GETODDS_API_KEY"
```

3. The same request in Python (standard library only):

```python
import json, os, urllib.request

req = urllib.request.Request(
    "https://getoddsapi.com/api/v1/odds?sport=NBA&market=spread&fresh_only=true&limit=50",
    headers={"Authorization": "Bearer " + os.environ["GETODDS_API_KEY"]},
)
with urllib.request.urlopen(req) as res:
    rows = json.load(res)["data"]
for row in rows:
    print(row["away"], "at", row["home"], row["side"], row["line"], row["american"], row["observed_at"])
```

4. Check `observed_at`, `age_seconds` and `stale` on every row before using a price. Full reference: https://getoddsapi.com/docs

## Use with Claude (MCP)

```bash
claude mcp add --transport http getodds https://getoddsapi.com/api/mcp \
  --header "Authorization: Bearer $GETODDS_API_KEY"
```

The MCP tools follow the key's source grants and share its allowance. Setup guide: https://getoddsapi.com/use-with-claude

## Pricing

| Plan | Allowance | Price |
| --- | --- | --- |
| Free key | 1,000 requests a day, 60 a minute | $0, no card |
| Developer Bundle | 10,000 requests or credits a month on each of four sources | $149 a month |

Free development allowance: 1,000 requests per UTC day and 60 per minute per account, with no payment step. Paid: the Developer Bundle at $149 per month, with 10,000 monthly requests or credits on each of four sources.
Details: https://getoddsapi.com/bundle

## Calculator


Canonical page: https://getoddsapi.com/odds-converter
Markdown version: https://getoddsapi.com/odds-converter.md
Language: English. Formula review date: 2026-11-06.

An odds converter expresses the same price as American odds, decimal odds and implied probability. For positive American odds, decimal odds equal one plus the price divided by 100. For negative odds, divide 100 by the absolute price and add one. Implied probability is one divided by decimal odds.

## Inputs

| Input | Default example | Instructions |
| --- | --- | --- |
| Odds | -110 | American -110 / +150, decimal 2.50, fractional 3/2, or 40%. |

## Formula

Positive American: d = 1 + a/100. Negative American: d = 1 + 100/|a|. Probability = 1/d.

## Worked example

+150 equals decimal 2.50, fractional 3/2 and a 40% implied probability.

| Result | Value | Working |
| --- | --- | --- |
| Implied probability | 52.381% | 100 ÷ 1.909091 |
| Fractional odds | 10/11 | Profit-to-stake ratio, reduced without intermediate rounding |
| Decimal odds | 1.9091 | Total return per unit staked |
| American odds | -110 | −100 ÷ (1.909091 − 1) |

## Assumptions and limits

Implied probability includes the bookmaker’s margin. It is not a measured prediction of the outcome.

Inputs are supplied by the user. These calculators do not fetch live sportsbook prices, estimate a win probability, or recommend selections. Monetary examples use USD. Calculations run in the browser without an account. A shared calculation URL contains its entered numbers.

## Questions and answers

### How does the odds converter work?

An odds converter expresses the same price as American odds, decimal odds and implied probability. For positive American odds, decimal odds equal one plus the price divided by 100. For negative odds, divide 100 by the absolute price and add one. Implied probability is one divided by decimal odds.

### What is the formula?

Positive American: d = 1 + a/100. Negative American: d = 1 + 100/|a|. Probability = 1/d.

### Can you show a worked example?

+150 equals decimal 2.50, fractional 3/2 and a 40% implied probability.

### What assumptions should I check?

Implied probability includes the bookmaker’s margin. It is not a measured prediction of the outcome.

### Does the result include the original stake?

Total return includes a cash stake; net profit subtracts it. A stake-not-returned bonus is explicitly treated differently. Probability and margin outputs are percentages, not cash payouts.

### Can I share my calculation?

Use Copy link to share the current inputs. The URL contains your entered numbers. Calculations run in your browser and do not require an account.

## Embedding

Embed: https://getoddsapi.com/embed/odds-converter
Keep a visible attribution link to the canonical explanation. Embed pages are noindex; use the canonical page for indexing and citations.

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Independent educational product, not affiliated with any sportsbook or pick’em operator. Results are arithmetic, not predictions or betting advice. Only participate where lawful and within limits you can afford.
Responsible gambling resources: https://www.ncpgambling.org/