Truth Table for NOR

What NOR means

NOR is the negation of OR. For two inputs, the output is true only when both inputs are false. In every other case, the output is false.

How to fill a NOR truth table

1. List all input combinations in a fixed order, usually: TT, TF, FT, FF or 1,1; 1,0; 0,1; 0,0.
2. Evaluate the OR part first.
   • OR is true if at least one input is true.
3. Negate that result.
   • If OR is true, NOR is false.
   • If OR is false, NOR is true.
4. Write the final output in the table for each row.

Quick pattern to remember

• T NOR T = F
• T NOR F = F
• F NOR T = F
• F NOR F = T

How to check your answer

Read each row aloud as: “neither input is true.” The output should be true only for the row where both inputs are false. If the completed table has more than one true output, it is incorrect.

Simplifying the final answer

If the exercise asks for a simplified result, identify the one row where NOR is true. That row corresponds to the condition both inputs are false. Use that idea to express the output clearly and consistently.