What does OR actually compute?

For each bit position, OR produces a 1 whenever either input bit (or both) is 1; the result is 0 only when both input bits are 0. It's the standard logical/bitwise OR, applied independently across every bit position.

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 OR runs across every nibble-aligned bit position of that shared width.

Why is A5 OR 3C equal to BD?

A5 is 10100101 and 3C is 00111100 in binary. Combining bit by bit with OR gives 10111101, which is BD in hex, a 1 at every position where either input had a 1.

How is OR different from AND and XOR?

OR needs only one bit to be 1 to produce a 1, making it useful for setting bits (turning specific flags on regardless of their prior state). AND requires both bits to be 1, and XOR requires the bits to differ; all three combine the same inputs very differently.

Hex OR Calculator - Bitwise OR of Two Hex Values

Overview

Introduction

Bitwise OR is the standard way to set specific bits within a hex-encoded value without disturbing any bits that are already 1.

This tool computes the bitwise OR of two hexadecimal values, so you can see exactly which bit positions end up set.

What Is Hex OR Calculator?

A calculator for the bitwise OR of two hex values: it compares the two values bit by bit and sets a 1 wherever either operand has a 1 at that position.

Like the other two-operand hex gate calculators in this category, it automatically left-pads the shorter operand with zero digits so both values line up bit-for-bit before combining them.

How Hex OR 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 OR, and the result is formatted as an uppercase hex string padded to that same shared width.

When To Use Hex OR Calculator

Use it to combine flag bits from two hex-encoded values, or to set specific bits of a value using a hex bitmask.

It's also a useful teaching tool for showing how OR behaves on real multi-bit hex data rather than single bits.

Often used alongside Hex AND Calculator, Hex NOR Calculator and Hex XOR 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.
Only combines two operands at a time; chain the tool manually if you need to OR together more than two values.

Examples

OR of two mixed bit patterns

Input

A: A5, B: 3C

Output

BD

A5 (10100101) OR 3C (00111100) = BD (10111101), a 1 at every position where either input had a 1.

ORing with zero leaves the other value unchanged

Input

A: A5, B: 00

Output

A5

ORing any value with 00 (all zero bits) leaves every bit of the other operand untouched.

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 an all-zero operand when you want to pass a value through unchanged while confirming the OR logic is wired correctly.

Developer Notes

Implemented with JavaScript BigInt: after zero-padding both operands to the same digit width, it computes `a | b` directly (no complement step), avoiding JavaScript's native 32-bit-limited bitwise operators for operands wider than 32 bits.

Hex OR Calculator Use Cases

Setting specific flag bits in a status byte or register using a hex bitmask
Teaching or demonstrating the OR logic gate using concrete multi-bit hex examples
Cross-checking a manually-computed OR result

Common Mistakes

Expecting OR to clear bits rather than set them; it can only turn 0s into 1s, never turn a 1 back into a 0.
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 ORing a value with 00 to confirm the pass-through behavior of an all-zero operand.
Compare the result with the Hex AND Calculator on the same inputs to see how AND and OR diverge on mixed bit patterns.

Hex OR Calculator