Probability Calculator Plus

Master probability and statistics with Probability Calculator — the most complete probability calculator for students, teachers, and data enthusiasts.

Whether you're studying for an exam, teaching a class, or working through real-world statistics problems, ProbCalc gives you instant answers with full step-by-step solutions so you truly understand the math.

- PROBABILITY CALCULATIONS -
• Basic Probability — Calculate P(A) from favorable and total outcomes
• Conditional Probability — Solve P(A|B) = P(A∩B) / P(B)
• Independent Events — Multiply probabilities across multiple events
• Dependent Events — P(A∩B) = P(A) × P(B|A)
• Venn Diagram Calculator — Input P(A) and P(B), instantly get P(A∩B), P(A∪B), P(A XOR B), and occurrence probabilities over N trials — complete with visual Venn diagram
• Custom Calculator — Enter values as fractions, decimals, or percentages

- STATISTICAL DISTRIBUTIONS -
• Binomial Distribution — P(X=k), mean, variance, and standard deviation
• Normal Distribution — P(a ≤ X ≤ b) with z-score computation and CDF
• Poisson Distribution — P(X=k) with λ parameter, mean, and variance

-RANDOM EXPERIMENT SIMULATOR -
Roll dice, flip coins, and draw cards — all with real probability charts:
• Dice: D4, D6, D8, D10, D12, D20 (roll up to 6 at once)
• Coins: Flip 1–10 coins simultaneously
• Cards: Draw from a standard 52-card deck
• Live frequency chart updates with every trial

- STEP-BY-STEP SOLUTIONS -
Every calculation shows the full working — formula, substitution, and result. Perfect for checking homework, preparing for exams, or learning how probability really works.

- CALCULATION HISTORY -
Every result is automatically saved. Search, review, and copy any previous calculation. Swipe to delete. Tap for full detail with all steps.

-REFERENCE GUIDE -
Built-in reference includes:
• Complete probability and distribution formulas
• Standard Normal Z-table (z = −3.0 to +3.0)
• Interactive combinations C(n,r) and permutations P(n,r) calculator

- DESIGNED FOR EVERYONE -
Clean, distraction-free interface with full Dark Mode support. Tap any result to copy it instantly. Works on iPhone and iPad.
No ads. No subscriptions. No internet required.

Perfect for:
• High school and university statistics courses
• AP Statistics, IB Math, A-Level, SAT/ACT prep
• College probability and statistics classes
• Teachers preparing lessons and examples
• Data analysts and business professionals

Probability is the measure of the likelihood that an event will occur. Probability is quantified as a number between 0 and 1, where, loosely speaking, 0 indicates impossibility and 1 indicates certainty.

Summary of probabilities:
Probability that both the events occur P(A ∩ B) = P(A) x P(B).
Probability that either of event occurs P(A U B) = P(A) + P(B) - P(A ∩ B).
Conditional Probability P(A | B) = P(A ∩ B) / P(B).
Conditional Probability P(B | A) = P(A ∩ B) / P(A).
Exclusive OR of A and B P(A XOR B) = P(A) + P(B) - 2 X P(A ∩ B).

Probability theory is used wi