How to Convert Byte Array to Hex String in C#: Complete Guide

Turning Bytes into Strings and Back: The Magic of Hexadecimal Code in C#

Have you ever wondered how a computer sees an image, music, or just a text file? It's all just a sequence of bytes. But bytes are not very convenient to display to a user or transmit in a URL. That's where the hexadecimal string (hex string) comes to the rescue — a compact and readable representation of binary data.

Imagine: you're writing a cryptographic module, working with hashes, transmitting binary data via JSON, or logging packet contents. And then — bam! — you need to turn a byte array into a readable string. Or vice versa, restore the original bytes from a hex string. Sounds familiar? This question is one of the most popular on Stack Overflow, and today we'll settle it once and for all. Welcome to pythonlib.ru — your guide in the world of programming.

Why Convert a Byte Array to a Hex String at All?

Let's get straight to the point. A byte array (byte[]) is raw data: numbers from 0 to 255. They are difficult for humans to read, and in some text protocols (HTTP, JSON) they can even break the format. A hex string solves both problems:

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• Compactness: one byte turns into two characters (e.g., 255 → "FF").
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• Safety: the string contains only safe characters (0-9, A-F).
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• Convenience: hex strings are easy to copy, compare, and log.
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You've probably seen such strings in MD5, SHA256 hashes, or authorization tokens. Now you know how it works "under the hood."

Method #1: The Classic — BitConverter (Simple and Fast)

The most popular way in C# is to use the built-in BitConverter class. It has been in .NET since the very first version and works without any extra fuss.

Converting byte[] → hex string

byte[] data = { 0x0F, 0x1A, 0xFF, 0x00 };\nstring hexString = BitConverter.ToString(data);\nConsole.WriteLine(hexString); // Output: 0F-1A-FF-00

Simple, right? But there's a nuance: a hyphen is inserted between character pairs. If the hyphen bothers you, it's easy to remove:

string hexString = BitConverter.ToString(data).Replace("-", "");\nConsole.WriteLine(hexString); // Output: 0F1AFF00

Pros: minimal code, built-in method, understandable for beginners.
\nCons: extra hyphen (needs removal), slight memory allocation for intermediate strings.

Reverse Conversion: hex string → byte[]

The reverse operation is a bit more complex. BitConverter only works one way. But we don't give up — let's write a simple parser:

public static byte[] HexStringToBytes(string hex)\n{\n    // Remove possible hyphens and spaces\n    hex = hex.Replace("-", "").Replace(" ", "");\n    int length = hex.Length;\n    byte[] bytes = new byte[length / 2];\n    for (int i = 0; i < length; i += 2)\n    {\n        bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);\n    }\n    return bytes;\n}\n\n// Usage:\nstring hex = "0F1AFF00";\nbyte[] result = HexStringToBytes(hex);\n// result: { 0x0F, 0x1A, 0xFF, 0x00 }

This method uses Convert.ToByte with base 16 — reliable and readable. However, for large arrays, Substring creates many temporary strings. For production code, it's better to use Span<T> or a loop with character indexing.

Method #2: Modern — Convert.ToHexString (.NET 5+)

Starting with .NET 5, Microsoft added the long-awaited Convert.ToHexString method. It works fast and without hyphens.

byte[] data = { 0x0F, 0x1A, 0xFF, 0x00 };\nstring hexString = Convert.ToHexString(data);\nConsole.WriteLine(hexString); // Output: 0F1AFF00

Beautiful! No hyphens, no Replace. And for the reverse operation, there is Co