NOR Logic Gate Calculator

Explore the NOR gate, a universal logic gate that outputs true only when all inputs are false.

Last updated: March 2026 | Digital Logic Tool

Input A

FALSE

Input B

FALSE

Logic Breakdown

1.Input A: FALSE (0)

2.Input B: FALSE (0)

3.OR Result: FALSE (0)

4.NOR Result (NOT OR): TRUE (1)

NOR Output (A ↓ B)

TRUE

NOR Truth Table

Input A	Input B	Output (A NOR B)
0	0	1
0	1	0
1	0	0
1	1	0

What is a NOR Gate?

The NOR gate is a digital logic gate that implements logical NOR (NOT OR). It outputs a HIGH signal (1) only when both inputs are LOW (0). If one or both inputs are HIGH (1), the output is LOW (0). This behavior makes it one of the most important gates in digital electronics.

NOR is a "universal gate" because any other logic gate—AND, OR, NOT, NAND, XOR, and XNOR—can be constructed using only NOR gates. This property makes NOR gates incredibly valuable in computer hardware design and integrated circuit manufacturing, as it simplifies production by using a single type of gate.

NOR Flash memory, used in SSDs and USB drives, is named after the NOR gate architecture. The gate is also fundamental in building complex circuits like multiplexers, decoders, and flip-flops that form the basis of all digital computers and processors.

How to Use the NOR Gate Calculator

Step-by-Step Process

Step 1: Toggle Input A by clicking the switch (OFF = 0/FALSE, ON = 1/TRUE)

Step 2: Toggle Input B by clicking its switch

Step 3: Observe the NOR output on the right side of the display

Step 4: Compare your inputs to the truth table to verify the logic

The NOR Logic Formula

Output = NOT(A OR B) = !(A ∨ B)

Example: How NOR Works

Let's evaluate all four possible input combinations:

Case 1: A=0, B=0

Both inputs are OFF → OR produces 0 → NOT(0) = 1 (TRUE)

Case 2: A=0, B=1

One input is ON → OR produces 1 → NOT(1) = 0 (FALSE)

Case 3: A=1, B=0

One input is ON → OR produces 1 → NOT(1) = 0 (FALSE)

Case 4: A=1, B=1

Both inputs are ON → OR produces 1 → NOT(1) = 0 (FALSE)

Frequently Asked Questions

Why is NOR called a 'universal gate'?

Because you can create any Boolean logic function using only NOR gates. You can build AND, OR, NOT, NAND, XOR, and all other gates from combinations of NOR gates.

What is the symbol for NOR?

In Boolean algebra, NOR is represented by the downward arrow (↓), also known as the Peirce arrow or Quine dagger. In circuit diagrams, it shows an OR gate with a bubble (NOT) on the output.

How does NOR relate to OR?

NOR is simply an OR gate with a NOT gate attached to its output. NOR = NOT(A OR B). If the OR output would be 1, then NOR outputs 0, and vice versa.

What is NOR Flash memory?

NOR Flash is a type of non-volatile computer memory where data is organized using NOR gate architecture. It's commonly used in USB drives, SSDs, and embedded systems because it allows random access.

Where are NOR gates used in practice?

NOR gates are used in memory chips (NOR Flash), microprocessors, signal processing, control systems, digital audio, and essentially any digital electronic device that requires decision-making logic.

How do you build a NOT gate from NOR gates?

Connect both inputs of a NOR gate together to the same signal. This is equivalent to NOT(A OR A) = NOT(A). A single input line connected to both inputs creates a NOT functionality.