{
  "slug": "odds-format-converter",
  "title": "Odds Format Converter (American, Decimal, Fractional)",
  "heading": "Odds Format Converter",
  "category": "math",
  "url": "https://www.revenuelab.fyi/toolbox/odds-format-converter",
  "summary": "Convert American, decimal, and fractional betting odds instantly.",
  "description": "US sportsbooks quote American odds (-110, +150), European exchanges and most odds-comparison sites quote decimal (1.91, 2.50), and UK bookmakers quote fractional (10/11, 3/2). They're the same number in three costumes, and mixing them up is the most common way bettors misjudge a price. This tool converts any one format to the other two so you can compare a line across books that quote differently, or sanity-check a payout before you place money. It also shows the payout on a $100 stake so the abstract number turns into something concrete. Enter odds in whichever format you have and the other two populate automatically along with implied probability, which strips out the vig-inflated percentage a single price implies. Use this before line shopping across books that display odds differently, before verifying a screenshot or bet slip, or when reading UK/Irish racing prices you're not used to. This is a conversion tool, not a probability model — it doesn't tell you whether a bet is good, only what the number actually means in another format.",
  "formula": "Decimal = 1 + (American/100) if positive, or 1 + (100/|American|) if negative. Fractional ≈ decimal − 1, reduced to lowest terms. Implied probability = 1 ÷ decimal.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=odds-format-converter",
  "inputs": [
    {
      "id": "format",
      "label": "Input format",
      "kind": "select",
      "hint": null,
      "default": "american",
      "options": [
        {
          "value": "american",
          "label": "American (e.g. -110, +150)"
        },
        {
          "value": "decimal",
          "label": "Decimal (e.g. 1.91)"
        }
      ]
    },
    {
      "id": "american",
      "label": "American odds",
      "kind": "number",
      "hint": null,
      "default": -110,
      "unit": null,
      "min": null,
      "max": null
    },
    {
      "id": "decimal",
      "label": "Decimal odds",
      "kind": "number",
      "hint": null,
      "default": 1.91,
      "unit": null,
      "min": 1.01,
      "max": null
    },
    {
      "id": "stake",
      "label": "Stake to illustrate payout",
      "kind": "number",
      "hint": null,
      "default": 100,
      "unit": "$",
      "min": 1,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "decimal",
      "label": "Decimal odds",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "american",
      "label": "American odds",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "fractional",
      "label": "Fractional odds",
      "format": "raw",
      "hint": null,
      "primary": false
    },
    {
      "id": "implied",
      "label": "Implied probability",
      "format": "percent",
      "hint": null,
      "primary": false
    },
    {
      "id": "profit",
      "label": "Profit on stake",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "payout",
      "label": "Total payout (stake + profit)",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Input format: American (e.g. -110, +150)",
      "American odds: -110",
      "Decimal odds: 1.91",
      "Stake to illustrate payout: 100 $"
    ],
    "outputs": [
      "Decimal odds: 1.909",
      "American odds: -110",
      "Fractional odds: 91/100",
      "Implied probability: 52.4%",
      "Profit on stake: $90.91",
      "Total payout (stake + profit): $190.91"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter input format.",
      "Enter american odds.",
      "Enter decimal odds.",
      "Enter stake to illustrate payout ($).",
      "Read your decimal odds on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "format": "american",
        "american": -65,
        "decimal": 1.146,
        "stake": 60
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "format": "american",
        "american": -110,
        "decimal": 1.91,
        "stake": 100
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "format": "american",
        "american": -175,
        "decimal": 3.056,
        "stake": 160
      }
    }
  ],
  "limitations": [
    "Results are rounded for display; the underlying calculation keeps full precision.",
    "Very large or very small inputs may hit floating-point limits in the browser.",
    "Inputs outside the accepted range are clamped rather than rejected."
  ],
  "faq": [
    {
      "q": "Why do American odds have a plus and minus sign?",
      "a": "Minus odds (-110) show how much you must stake to win $100. Plus odds (+150) show how much you win on a $100 stake. Favorites carry minus odds, underdogs carry plus odds, and even-money bets sit exactly at +100/-100, which equals decimal 2.00."
    },
    {
      "q": "Is decimal odds the same as the payout multiplier?",
      "a": "Yes. Decimal odds already include your stake. A $50 bet at 2.50 decimal returns $125 total ($75 profit), because 50 × 2.50 = 125. American and fractional odds only describe the profit, so decimal is the easiest format for quick mental math."
    },
    {
      "q": "Why does a fractional conversion sometimes look odd, like 21/20?",
      "a": "Fractional odds in the UK are often rounded to trading conventions such as 10/11 or 4/5 rather than exact decimals, so a converted value like 21/20 is mathematically correct but not a price you'd typically see quoted at a shop. Treat the fraction as accurate math, not a guaranteed market price."
    },
    {
      "q": "Which format should I use to compare two sportsbooks?",
      "a": "Decimal is easiest for comparison because higher is always better regardless of favorite or underdog status. Comparing -105 to -110 or +120 to +115 requires more mental math than comparing 1.95 to 1.91."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/implied-probability-calculator",
    "https://www.revenuelab.fyi/toolbox/no-vig-fair-odds",
    "https://www.revenuelab.fyi/toolbox/breakeven-win-rate-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Odds Format Converter (American, Decimal, Fractional) (https://www.revenuelab.fyi/toolbox/odds-format-converter)"
}