Base64 to Hex

What Is Base64 to Hex Conversion?

Base64 to hex conversion transforms data between two common binary-to-text encoding schemes. Base64 represents binary data using 64 ASCII characters (A-Z, a-z, 0-9, +, /), encoding every 3 bytes as 4 characters. Hexadecimal represents each byte as exactly two characters from a 16-symbol alphabet (0-9, a-f). Converting between these formats is a two-step process: decode the Base64 string into its raw bytes, then re-encode those bytes in the target format.

Hexadecimal notation is the standard representation for binary data in low-level programming, cryptography, and network protocols. Each hex character maps directly to a 4-bit nibble, making it straightforward to read individual byte values. A SHA-256 hash, for example, is almost always displayed as a 64-character hex string. Base64, by contrast, is optimized for compactness — the same hash takes only 44 characters in Base64 — and is the standard encoding for email attachments (MIME), data URIs, and API payloads.

Both encodings are defined in RFC 4648. The conversion between them is lossless: no data is added or removed, only the textual representation changes. This makes Base64-to-hex conversion a routine operation when debugging encrypted payloads, inspecting certificate fingerprints, or verifying hash outputs across systems that use different display formats.

Why Use This Base64 to Hex Converter?

This tool converts between Base64 and hexadecimal directly in your browser. No data leaves your machine, and the conversion happens in real time as you type.

Base64 to Hex Use Cases

Base64 vs Hexadecimal Encoding

Base64 and hexadecimal both convert binary data to printable text, but they make different trade-offs between compactness and readability. The table below summarizes the key differences.

Conversion Examples

The table below shows identical byte sequences in their Base64 and hexadecimal representations. Notice that hex output is always exactly twice the byte count, while Base64 length equals ceil(byteCount / 3) * 4.

How the Conversion Works

Converting Base64 to hexadecimal is a two-phase process. First, the Base64 string is decoded into raw bytes by mapping each character to its 6-bit value, concatenating the bits, and splitting them into 8-bit bytes (discarding padding). This step reverses the encoding defined in RFC 4648 Section 4.

Second, each byte is converted to its two-digit hexadecimal representation. The byte value 0-255 maps to 00-ff. A byte like 0x4F (decimal 79) becomes the two characters '4' and 'f'. The complete hex string is simply the concatenation of all two-character pairs. The reverse direction (hex to Base64) applies these steps in reverse order: parse hex pairs into bytes, then Base64-encode the result.

Code Examples

These runnable snippets show how to convert between Base64 and hex in JavaScript, Python, Go, and the command line. Each example covers both conversion directions.

// Base64 to Hex
function base64ToHex(b64) {
  const raw = atob(b64)
  return Array.from(raw, c =>
    c.charCodeAt(0).toString(16).padStart(2, '0')
  ).join('')
}
base64ToHex('SGVsbG8=') // → "48656c6c6f"

// Hex to Base64
function hexToBase64(hex) {
  const bytes = hex.match(/.{1,2}/g).map(b => parseInt(b, 16))
  return btoa(String.fromCharCode(...bytes))
}
hexToBase64('48656c6c6f') // → "SGVsbG8="

// Node.js Buffer shorthand
Buffer.from('SGVsbG8=', 'base64').toString('hex')   // → "48656c6c6f"
Buffer.from('48656c6c6f', 'hex').toString('base64')  // → "SGVsbG8="

import base64, binascii

# Base64 to Hex
b64_str = 'SGVsbG8='
raw_bytes = base64.b64decode(b64_str)
hex_str = raw_bytes.hex()            # → '48656c6c6f'
# or: binascii.hexlify(raw_bytes).decode()

# Hex to Base64
hex_str = '48656c6c6f'
raw_bytes = bytes.fromhex(hex_str)
b64_str = base64.b64encode(raw_bytes).decode()  # → 'SGVsbG8='

# One-liner for quick conversion
base64.b64encode(bytes.fromhex('deadbeef')).decode()  # → '3q2+7w=='

package main

import (
    "encoding/base64"
    "encoding/hex"
    "fmt"
)

func main() {
    // Base64 to Hex
    raw, _ := base64.StdEncoding.DecodeString("SGVsbG8=")
    hexStr := hex.EncodeToString(raw)
    fmt.Println(hexStr) // → "48656c6c6f"

    // Hex to Base64
    raw2, _ := hex.DecodeString("48656c6c6f")
    b64Str := base64.StdEncoding.EncodeToString(raw2)
    fmt.Println(b64Str) // → "SGVsbG8="
}

# Base64 to Hex (using base64 + xxd)
echo -n 'SGVsbG8=' | base64 -d | xxd -p
# → 48656c6c6f

# Hex to Base64
echo -n '48656c6c6f' | xxd -r -p | base64
# → SGVsbG8=

# OpenSSL alternative
echo -n 'SGVsbG8=' | openssl base64 -d | xxd -p
# → 48656c6c6f

Frequently Asked Questions