# Games & Betting Math calculators

> Odds conversion, parlay and hedge bets, arbitrage, expected value, Kelly criterion, poker outs and Elo ratings — probability mathematics, not tips.

8 calculators. HTML index: https://tttkmbb.com/gaming · JSON: https://tttkmbb.com/api/v1/calculators?category=gaming

- [Odds Converter](https://tttkmbb.com/gaming/odds-converter.md): 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. Tool: `convert_betting_odds`.
- [Parlay Odds Calculator](https://tttkmbb.com/gaming/parlay-odds.md): Multiplies the decimal odds of 2–15 independent legs into the combined parlay (accumulator) price and reports the total payout, profit and implied probability of all legs winning. Tool: `calculate_parlay_odds`.
- [Hedge Bet Calculator](https://tttkmbb.com/gaming/hedge-bet.md): Computes the stake to place on the opposite outcome so that the profit is the same whether the original bet or the hedge wins, and the profit (or loss) that this locks in. Tool: `calculate_hedge_bet`.
- [Arbitrage Betting Calculator](https://tttkmbb.com/gaming/arbitrage-bet.md): Sums the implied probabilities of the best decimal odds available on each outcome of a 2- or 3-way market, tests whether an arbitrage exists (sum below 100 %) and splits a total stake so that every outcome returns the same payout. Tool: `calculate_arbitrage_bet`.
- [Bet Expected Value Calculator](https://tttkmbb.com/gaming/bet-expected-value.md): Computes the expected value of a bet from its decimal odds, your estimated win probability and the stake, together with the implied probability, the edge in percentage points and the fair (break-even) decimal odds. Tool: `calculate_bet_expected_value`.
- [Kelly Criterion Calculator](https://tttkmbb.com/gaming/kelly-criterion.md): Computes the Kelly stake fraction f* = (b·p − q)/b from decimal odds and an estimated win probability, the recommended stake for a bankroll at full or fractional Kelly, and the expected logarithmic growth rate per bet. Tool: `calculate_kelly_stake`.
- [Poker Outs Calculator](https://tttkmbb.com/gaming/poker-outs.md): Computes the exact probability of hitting one of your outs by the next card or by the river in Texas hold'em from the number of outs and unseen cards, expressed as a percentage and as odds against, and compares it with the rule of 2 and 4 estimate. Tool: `calculate_poker_outs`.
- [Elo Rating Calculator](https://tttkmbb.com/gaming/elo-rating.md): Computes the expected score of two players from their Elo ratings with the logistic formula E = 1/(1 + 10^((R_b − R_a)/400)) and the rating change of each after a win, draw or loss for a given K-factor. Tool: `calculate_elo_rating`.