{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"odds-converter"},"result":{"entity_type":"calculator","id":"odds-converter","calculator_id":"odds-converter","canonical_url":"https://tttkmbb.com/gaming/odds-converter","name":"Odds Converter","title":"Odds Converter – American, Decimal and Fractional Odds with Implied Probability and Payout","category":"gaming","category_name":"Games & Betting Math","tool_name":"convert_betting_odds","featured_mcp_tool":true,"description":"Converts betting odds between American (moneyline), decimal (European) and fractional (UK) formats, auto-detecting the input format, and reports the implied probability, profit and total return for a stake.","use_when":"You have odds in one format and need the other two, the implied probability of a price, or the payout of a stake at those odds.","do_not_use_when":"You need the combined price of several selections (use parlay-odds), the value of a bet given your own probability estimate (use bet-expected-value), or a bookmaker's margin across a whole market (use arbitrage-bet). Mathematics only; not gambling advice.","inputs":[{"name":"odds","label":"Odds","type":"string","required":true,"description":"Odds in any format: American +150 or -200, decimal 2.50, fractional 3/2 or 3-2, or evens.","example":"+150"},{"name":"format","label":"Input format","type":"enum","required":false,"default":"auto","values":[{"value":"auto","label":"Auto-detect"},{"value":"american","label":"American / moneyline (+150, -200)","aliases":["moneyline","us"]},{"value":"decimal","label":"Decimal / European (2.50)","aliases":["european","eu"]},{"value":"fractional","label":"Fractional / UK (3/2)","aliases":["uk","fraction","british"]}],"description":"Format of the odds input. Auto: a/b or a-b with digits on both sides is fractional, a sign or an integer of 100 or more is American, anything else is decimal.","example":"auto"},{"name":"stake","label":"Stake","type":"number","required":false,"default":100,"max":1000000000,"exclusive_min":0,"description":"Stake used for the profit and return outputs (any currency).","example":100}],"outputs":[{"name":"american","label":"American odds","type":"string","decimals":4,"description":"Moneyline price with sign, rounded to a whole number: +X wins X per 100 staked, -X needs X staked to win 100."},{"name":"decimal","label":"Decimal odds","type":"number","decimals":3,"description":"Total return per unit staked, including the stake."},{"name":"fractional","label":"Fractional odds","type":"string","decimals":4,"description":"Profit/stake as a fraction reduced with the GCD, exactly equal to decimal − 1."},{"name":"implied_probability_percent","label":"Implied probability","type":"number","unit":"%","decimals":2,"description":"100 / decimal: the break-even win probability the price implies (includes the bookmaker margin)."},{"name":"profit_on_stake","label":"Profit if it wins","type":"number","decimals":2,"description":"stake × (decimal − 1)."},{"name":"total_return","label":"Total return","type":"number","decimals":2,"description":"stake × decimal (profit plus the returned stake)."},{"name":"detected_format","label":"Input format used","type":"string","decimals":4,"description":"Format the input was parsed as (american, decimal or fractional)."}],"input_schema":{"type":"object","properties":{"odds":{"description":"Odds in any format: American +150 or -200, decimal 2.50, fractional 3/2 or 3-2, or evens.","type":"string","examples":["+150"]},"format":{"description":"Format of the odds input. Auto: a/b or a-b with digits on both sides is fractional, a sign or an integer of 100 or more is American, anything else is decimal.","type":"string","enum":["auto","american","decimal","fractional"],"default":"auto","examples":["auto"]},"stake":{"description":"Stake used for the profit and return outputs (any currency).","type":"number","maximum":1000000000,"exclusiveMinimum":0,"default":100,"examples":[100]}},"additionalProperties":false,"required":["odds"]},"output_schema":{"type":"object","properties":{"american":{"description":"Moneyline price with sign, rounded to a whole number: +X wins X per 100 staked, -X needs X staked to win 100.","type":"string"},"decimal":{"description":"Total return per unit staked, including the stake.","type":"number"},"fractional":{"description":"Profit/stake as a fraction reduced with the GCD, exactly equal to decimal − 1.","type":"string"},"implied_probability_percent":{"description":"100 / decimal: the break-even win probability the price implies (includes the bookmaker margin). Unit: %.","type":"number","x-unit":"%"},"profit_on_stake":{"description":"stake × (decimal − 1).","type":"number"},"total_return":{"description":"stake × decimal (profit plus the returned stake).","type":"number"},"detected_format":{"description":"Format the input was parsed as (american, decimal or fractional).","type":"string"}}},"formula":"decimal = 1 + american/100 (american > 0) or 1 + 100/|american| (american < 0); decimal = 1 + a/b (fractional a/b); american = +100·(decimal − 1) if decimal ≥ 2, else −100/(decimal − 1); fractional = (decimal − 1) reduced with the GCD; implied_probability_percent = 100/decimal; total_return = stake × decimal","method":"Odds of ±100 are evens (2.00, 1/1). The fractional output is the exact reduced fraction of decimal − 1; when a decimal price is a rounded traditional fraction (1.91 for 10/11) the nearest fraction with denominator ≤ 20 within ±0.005 is reported in the notes. Probability mathematics only; not gambling advice.","sources":[{"name":"Odds – moneyline, decimal and fractional odds and implied probability (Wikipedia)","url":"https://en.wikipedia.org/wiki/Odds","type":"reference","retrieved_at":"2026-09-24"},{"name":"Mathematics of bookmaking – overround and implied probability (Wikipedia)","url":"https://en.wikipedia.org/wiki/Mathematics_of_bookmaking","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"+150 American, stake 100","inputs":{"odds":"+150"},"expected":{"american":"+150","decimal":2.5,"fractional":"3/2","implied_probability_percent":40,"profit_on_stake":150,"total_return":250},"url":"https://tttkmbb.com/api/v1/calculate/odds-converter?odds=%2B150"},{"name":"-200 American","inputs":{"odds":"-200","format":"auto","stake":100},"expected":{"american":"-200","decimal":1.5,"fractional":"1/2","implied_probability_percent":66.67,"profit_on_stake":50,"total_return":150},"url":"https://tttkmbb.com/api/v1/calculate/odds-converter?odds=-200&format=auto&stake=100"}],"faq":[{"q":"How is the format detected automatically?","a":"Digits on both sides of a slash or dash (3/2, 3-2) mean fractional; a leading + or − sign, or a whole number of 100 or more (150), means American; anything else (2.50, 1.91) is decimal. Set format explicitly if an input is ambiguous."},{"q":"Why does 1.91 give 91/100 and not 10/11?","a":"The fractional output is the exact reduced value of decimal − 1. Bookmakers display 10/11 rounded to 1.91; the closest such traditional fraction (denominator ≤ 20, within ±0.005) is listed in the notes when it differs."},{"q":"Why do implied probabilities of a market add up to more than 100 %?","a":"Each price includes the bookmaker margin (overround). Dividing each implied probability by their sum removes it; arbitrage-bet reports the sum for a whole market."}],"tags":["odds converter","american odds","decimal odds","fractional odds","implied probability","moneyline"],"related":[{"calculator_id":"parlay-odds","reason":"Combine several decimal prices into one accumulator price."},{"calculator_id":"bet-expected-value","reason":"Compare the implied probability with your own estimate to find the expected value."},{"calculator_id":"percentage","reason":"General percent arithmetic on stakes and returns."}],"links":{"html":"https://tttkmbb.com/gaming/odds-converter","markdown":"https://tttkmbb.com/gaming/odds-converter.md","json":"https://tttkmbb.com/gaming/odds-converter.json","api":"https://tttkmbb.com/api/v1/calculate/odds-converter","schema":"https://tttkmbb.com/api/v1/calculators/odds-converter","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:45:07Z"}