Probability Calculator
Calculate the probability of events, including single events, multiple events, c...Calculate the probability of events, including single events, multiple events, combinations, and permutations. Perfect for coin flips, dice rolls, car...
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Probability Calculator Features
Calculate any probability
Why Use Probability Calculator?
All Probability Types
Calculate single event, multiple event, combinations, permutations, and binomial probability all in one tool.
Common Scenarios
Built-in support for coin flips, dice rolls, card draws, and custom probability scenarios with easy inputs.
Multiple Formats
Results displayed as fraction, decimal, and percentage. Choose the format that works best for your needs.
Formula Reference
See the formulas used and understand how probability calculations work. Learn while you calculate.
Common Use Cases
Probability for every scenario
Statistics & Math Class
Check homework problems and understand probability concepts. Great for learning combinations, permutations, and probability theory.
Games & Gambling
Calculate odds for board games, card games, dice games, and other games of chance. Understand your true chances of winning.
Scientific Research
Calculate statistical probabilities for experiments and research. Determine likelihood of outcomes in controlled trials.
Risk Assessment
Evaluate probability of multiple events occurring for business decisions, insurance calculations, or project planning.
How It Works
Select Calculation Type
Choose what type of probability you want to calculate - single event, multiple events, combinations, permutations, or binomial.
Enter Your Values
Input the relevant numbers - favorable outcomes, total outcomes, or individual event probabilities depending on calculation type.
For Multiple Events
Choose AND (both happen), OR (either happens), or NOT (complement) to combine event probabilities.
Get Results
See probability as fraction, decimal, and percentage. Review the formula used to understand the calculation.
Pro Tips for Probability
Remember the Basics
Probability always ranges from 0 (impossible) to 1 (certain). If your result is outside this range, double-check your inputs.
Independent vs Dependent
Use simple multiplication only for independent events. For dependent events (like drawing cards without replacement), calculations are more complex.
The Complement Trick
Sometimes it's easier to calculate P(not A) and subtract from 1. Example: P(at least one head in 3 flips) = 1 - P(no heads) = 1 - 0.125 = 0.875.
Check with Fractions
When possible, verify your answer makes sense. The probability of rolling a 6 should be 1/6, not 1/36. Context helps catch errors.
Frequently Asked Questions
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