OR Probability Calculator P(A ∪ B)

Calculate union probability P(A or B) = P(A) + P(B) - P(A ∩ B) for two events.

How It Works & Processing Standards

Enter values above to calculate results automatically. Check each input field for guidance and units.

Your input data is never sent to any server and is securely processed on your device.

Current Limits

  • Maximum input length: 100,000 characters

OR Probability Calculator P(A ∪ B) is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.

How to Use OR Probability Calculator P(A ∪ B)

  1. 1
    Enter P(A)Type probability of A.
  2. 2
    Enter P(B)Type probability of B.
  3. 3
    Enter P(A ∩ B)Type overlap intersection probability (0 if mutually exclusive).

Common Use Cases

  • Finding chance of drawing an Ace or a Heart from a deck
  • Assessing backup power system activation chances
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