Statistics & Probability

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AND Probability Calculator.

Calculate the probability of two independent events both occurring.

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Set your values

Results update as you type.

probability: 0.2

probability

0.200000

Results update automatically as you type.

Use Cases

Verify probability calculations quickly

Instead of manually multiplying probabilities, use this tool to double-check your work. It's especially handy when dealing with multiple independent events or when you need a quick reference.

Example: Check that P(A)=0.3 and P(B)=0.2 gives 0.06, not 0.5.

Frequently Asked Questions

What does the AND Probability Calculator do?
It calculates the probability that both independent events A and B occur, known as the joint probability. For independent events, this is simply P(A) × P(B). You enter the probabilities of each event, and the calculator gives you the combined probability.
How do I use the calculator?
Enter the probability of event A (P(A)) and the probability of event B (P(B)) as decimals between 0 and 1. The calculator multiplies them to give the probability that both events happen. For example, if P(A)=0.5 and P(B)=0.4, the result is 0.2.
Can I use percentages instead of decimals?
The calculator expects probabilities as decimals (e.g., 0.5 for 50%). If you have percentages, convert them by dividing by 100. For instance, 25% becomes 0.25. The result will be a decimal, which you can convert back to a percentage by multiplying by 100.

Tips & Common Mistakes

Tips

  • Ensure both P(A) and P(B) are between 0 and 1. If you have percentages, convert them to decimals first (e.g., 50% becomes 0.5).
  • Remember that this calculator only works for independent events. If events are dependent, the formula is different and this tool won't be accurate.
  • Double-check your inputs for typos. A small error in decimal placement can significantly change the result.
  • Use the result as a reference for your own analysis; it's not a substitute for professional statistical advice.

Common Mistakes to Avoid

  • Entering percentages as whole numbers (e.g., 50 instead of 0.5) leads to incorrect results. Always convert to decimals.
  • Using this calculator for dependent events. The multiplication rule only applies when events are independent.
  • Misinterpreting the result: the output is the probability that both events occur, not the probability of either event occurring.

Last updated: August 13, 2026