Probability Calculator - Independent Events & Binomial | WebToolsPro

Probability Calculator Studio

Solve complex probability scenarios, independent events, and binomial distributions instantly.

Enter the probability of each event occurring (assuming they are independent).
Probability of Event A
%
Probability of Event B
%
Probability of A and B

0%

( 0.000 )
Enter Values
P (A or B) 0% 0.00
P (Not A) 0% 0.00
P (A exactly, not B) 0% 0.00
Calculate the probability of an event happening a specific number of times.
Probability of Success (1 trial)
%
Number of Trials (n)
Times
Target Successes (k)
Hits
Probability of EXACTLY 0 Successes

0%

( 0.000 )
Enter Values
P (Less than target) 0%
P (More than target) 0%
P (At least 1 success) 0%

How To Use

Two Events: Use the first tab if you know the probabilities of two separate events and want to know the chances of both happening, or either one happening.
Repeated Trials: Use the second tab for scenarios like flipping coins or rolling dice. Enter the chance of success, total attempts, and target successes.
Formats: The results automatically display in both Percentage (%) and Decimal formats to help with different types of math homework.

Why Use This Tool?

Advanced Binomial Math: Calculating repeated trials manually requires complex factorial math. Our tool handles this instantly using the Binomial Distribution formula.
Comprehensive Views: Instead of just giving one answer, we provide the probability of getting "less than" or "more than" your target instantly.
100% Private & Fast: Because there is no server processing, the complex formulas run instantly and securely inside your browser.

Frequently Asked Questions

What does "Independent Events" mean?

Independent events are events where the outcome of one does not affect the outcome of the other. For example, flipping a coin and rolling a die are independent. Our first tab assumes the two events you enter are independent.

What is P(A and B) vs P(A or B)?

P(A and B) is the probability that both events will happen simultaneously (usually a smaller chance). P(A or B) is the probability that at least one of the events will happen (usually a much larger chance).

Can I use this for Coin Tosses or Dice Rolls?

Yes! Use the "Repeated Trials" tab. For a coin toss, the Probability of Success is 50%. For rolling a specific number on a 6-sided die, the Probability of Success is approximately 16.66% (1/6). Enter your trials and calculate!