Statistics & Probability

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Three-Event Probability Calculator.

Calculate the joint probability of three independent events.

On-device calculationNo signup
01

Set your values

Results update as you type.

probability: 0.05

probability

0.050000
percent: 5

percent

5.000000

Results update automatically as you type.

Use Cases

Quality Control

Determine the probability that three independent components all work correctly in a system, useful for reliability analysis.

Example: If each component has a 95% success rate, the probability all three work is 0.95 × 0.95 × 0.95 = 0.8574.

Weather Forecasting

Estimate the chance that three independent weather conditions (e.g., sunny, dry, and calm) all occur on a given day.

Example: If P(sunny)=0.6, P(dry)=0.7, P(calm)=0.8, then joint probability = 0.6 × 0.7 × 0.8 = 0.336.

Frequently Asked Questions

What does this calculator do?
This calculator computes the joint probability of three independent events. You enter the probabilities of each event (P(A), P(B), P(C)), and it multiplies them together to give the probability that all three events occur simultaneously.
How is the joint probability calculated?
For independent events, the joint probability is the product of their individual probabilities: P(A and B and C) = P(A) × P(B) × P(C). This calculator performs that multiplication automatically.
Can I use this for dependent events?
No, this calculator is specifically for independent events. If events are dependent, the joint probability requires conditional probabilities, which this tool does not account for.

Tips & Common Mistakes

Tips

  • Ensure each probability is between 0 and 1. Use decimals (e.g., 0.5) or percentages (e.g., 50%) – the calculator accepts both.
  • Double-check that the events are truly independent. If one event affects another, this calculator will not give accurate results.
  • For a quick check, remember that the joint probability will always be less than or equal to the smallest individual probability.

Common Mistakes to Avoid

  • Entering probabilities as whole numbers (e.g., 50 instead of 0.5) – always use decimal or percentage format.
  • Using this calculator for dependent events, which leads to incorrect joint probabilities.
  • Forgetting to convert percentages to decimals if the calculator expects decimal input – but this tool handles both, so just be consistent.

Last updated: August 13, 2026