- Fraction Calculator
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- Probability Calculator
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Binomial Probability CalculatorCalculate binomial probability P(X=k) with the formula C(n,k)·pᵏ·(1−p)^(n−k). Get exact, cumulative probabilities, mean and standard deviation.
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Powerball Odds Calculator (US)Calculate Powerball odds for the jackpot and every prize tier (US rules: 5 of 69 white balls + 1 of 26 red). See your chance per ticket and across multiple lines.
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Mega Millions Odds CalculatorCalculate your Mega Millions jackpot odds (US lottery). Uses 1 / (C(70,5)×25) = 1 in 302,575,350 with a configurable ball matrix.
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Standard Error of a Proportion CalculatorCalculate the standard error of a sample proportion using SE = sqrt(p(1-p)/n). Enter your proportion and sample size for instant, accurate results.
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A/B Test Significance CalculatorCheck if your A/B test result is statistically significant. Enter visitors and conversions for each variant to get Z-score, p-value, uplift, and a verdict.
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Lottery Expected Value CalculatorCalculate the expected value of a lottery ticket from the jackpot, odds, and ticket price. See if a ticket is worth it in the long run.
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D&D Advantage / Disadvantage Dice CalculatorCalculate your chance to hit a d20 target number with Advantage, Disadvantage, or a normal roll in Dungeons & Dragons 5e.
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Law of Total Probability CalculatorCompute P(A) from conditional and partition probabilities using the law of total probability: P(A) = Σ P(A|Bᵢ)·P(Bᵢ). Supports up to 3 events.
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Probability of Rolling a Specific Sum CalculatorFind the exact probability of rolling a chosen sum with any number of dice and sides. Uses convolution counting: P = (ways to make sum) / sides^n.
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Cumulative Binomial Probability CalculatorCompute cumulative binomial probability P(X≤k) for n trials with success probability p. Also returns P(X=k), P(X>k), P(X≥k) and the mean.
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Probability X Greater Than a Value (Normal Distribution)Compute P(X > x) for a normal distribution from mean, standard deviation, and a value. Returns the right-tail probability, z-score, and percentage.
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Parlay Odds CalculatorCalculate parlay payout and combined decimal odds for multi-leg bets. Enter your stake and up to 6 legs to see total payout and profit instantly.
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Hypergeometric Probability CalculatorCompute hypergeometric probabilities P(X=k), cumulative P(X≤k) and P(X≥k), plus mean and variance for sampling without replacement.
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Normal Probability Between Two X Values CalculatorFind P(a<X<b) for a normal distribution. Enter the mean, standard deviation and two X values to get the probability and z-scores instantly.
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Probability of At Most k Successes (Binomial) CalculatorCompute the binomial cumulative probability P(X ≤ k) for n trials with success probability p. Free, instant, with mean and complement.
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Probability of Exactly K Heads in N Flips CalculatorCompute the probability of getting exactly k heads in n coin flips using the binomial formula P = C(n,k) p^k (1-p)^(n-k). Free and instant.
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Probability of At Least One Success in n TrialsCalculate the probability of at least one success in n independent trials using P = 1 − (1−p)^n. Free, instant complement-rule probability calculator.
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Card Drawing Probability CalculatorCalculate the probability of drawing a given number of specific cards from a standard 52-card deck using the hypergeometric distribution.
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Probability of Rolling at Least One SixCalculate the probability of rolling at least one six with n dice using P = 1 − (5/6)^n. Get the exact percentage and decimal odds instantly.
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Binomial Probability CalculatorCalculate binomial probability P(X=k) for n trials with success probability p. Get exact, cumulative probabilities, mean, variance and standard deviation.
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Normal Distribution Probability CalculatorCalculate normal distribution probabilities P(X<x) and P(X>x) from a value, mean and standard deviation using the standard normal CDF.
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Normal CDF — Probability Less Than Z CalculatorCompute P(Z < z) = Φ(z), the standard normal cumulative probability below a z-score, plus upper tail and percentile. Optional μ and σ to standardize.
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F1 Score CalculatorCalculate the F1 score, precision, and recall from True Positives, False Positives, and False Negatives. Free machine-learning classification metric tool.
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Poker Hand Probability CalculatorCalculate the probability and odds of being dealt any 5-card poker hand from a standard 52-card deck, from royal flush to high card.
