What does XNOR actually compute?

XNOR is NOT(A XOR B): for each bit position, the result is 1 when the two input bits are equal (both 0 or both 1), and 0 when they differ. Because of that, XNOR is sometimes called the "equivalence" or "bit-match" operation.

What happens if my two values have different lengths?

The shorter value is left-padded with leading zero digits until it matches the longer value's digit count, then XNOR runs across every nibble-aligned bit position of that shared width, the same padding rule the Hex NOR Calculator uses.

Why is A5 XNOR 3C equal to 66?

A5 is 10100101 and 3C is 00111100 in binary. Their XOR is 10011001 (1 wherever the bits differ), which is 99 in hex. NOT of 99 is 01100110, which is 66, the bit positions that agree between A5 and 3C.

How is XNOR different from NOR?

NOR is NOT(A OR B), which is 1 only where both bits are 0. XNOR is NOT(A XOR B), which is 1 wherever the two bits match, whether that match is 0-and-0 or 1-and-1. They agree on all-zero inputs but diverge as soon as any 1 bits appear.

Hex XNOR Calculator - Bitwise XNOR of Two Hex Values

Overview

Introduction

XNOR flags where two values agree, bit for bit, which makes it useful anywhere you need a fast "are these bits equal" comparison rather than a full numeric equality check.

This tool computes the bitwise XNOR of two hexadecimal values, so you can see exactly which bit positions match between them.

What Is Hex XNOR Calculator?

A calculator for the bitwise XNOR (NOT-XOR) of two hex values: it XORs the two values together bit by bit, then inverts every bit of that result, leaving a 1 everywhere the original bits matched.

Like the Hex NOR Calculator, it automatically left-pads the shorter operand with zero digits so both values line up bit-for-bit before combining them.

How Hex XNOR Calculator Works

Both Value A and Value B are validated as hex strings, then the shorter is left-padded with leading zero digits to match the longer value's digit count.

The padded values are combined bit-by-bit with XOR, and the XOR result is then complemented (every bit flipped) across that same width to produce the final XNOR output.

When To Use Hex XNOR Calculator

Use it to quickly see which bit positions are identical between two hex-encoded values, e.g. two flag bytes or two register snapshots.

It's also a useful teaching tool for showing how XNOR behaves as the logical complement of XOR across real multi-bit data.

Often used alongside Hex NOR Calculator and Hex NOT Calculator.

Features

Advantages

Automatically handles operands of different lengths by zero-padding, so you don't have to align widths by hand first.
Works on arbitrarily long hex values via BigInt, not limited to a fixed 8/16/32/64-bit width.
Instant, deterministic, fully client-side.

Limitations

Zero-padding the shorter operand assumes you want it treated as a smaller number within a larger field; pad manually first if your context expects different alignment.
A result bit of 1 only tells you the two source bits matched, not which value they matched at (both 0 or both 1); check the individual inputs if that distinction matters.

Examples

XNOR of two complementary nibble patterns

Input

A: F0, B: 0F

Output

F0 (11110000) XOR 0F (00001111) = FF (11111111), since every bit position differs; NOT of FF is 00.

XNOR of two mixed bit patterns

Input

A: A5, B: 3C

Output

A5 (10100101) XOR 3C (00111100) = 99 (10011001); NOT of 99 is 66 (01100110), marking every position where A5 and 3C agreed.

Best Practices & Notes

Best Practices

Confirm both values are the width you intend before relying on the auto-padding, since a short operand gets left-padded with zeros.
Use the XNOR result together with the Hex NOT Calculator to double-check the intermediate XOR step if a result looks surprising.

Developer Notes

Implemented with JavaScript BigInt: after zero-padding both operands to the same digit width, it computes (mask XOR (a XOR b)) where mask is all-1s across that width, equivalent to NOT(A XOR B) without JavaScript's native 32-bit-limited bitwise operators getting in the way.

Hex XNOR Calculator Use Cases

Comparing two hex-encoded flag bytes or register snapshots for matching bits
Teaching or demonstrating the XNOR logic gate using concrete multi-bit hex examples
Cross-checking a manually-computed XNOR result

Common Mistakes

Reading an XNOR result as a numeric difference; it only marks bit-level agreement, not a magnitude or distance between the two values.
Forgetting that a short operand gets zero-padded on the left, which can change the intended meaning if it was meant to be right-aligned instead.

Tips

Try the Hex NOR Calculator on the same two inputs to compare how the two closely-related gates diverge once any 1 bits are involved.
A full-width all-F output means the two values are bit-for-bit identical at that width.

Hex XNOR Calculator