How do I encode a string to Base64?

Paste your text into a Base64 encoder and click encode. The Base64 output appears instantly. Each 3 bytes of input produces 4 Base64 characters, so the output is about 33% larger than the input.

Why would I need to encode something in Base64?

Base64 converts binary or special-character text into a safe ASCII string that can travel through systems that only support text. Common uses: embedding data in JSON, sending binary in email, passing data in URLs, and storing secrets in config files.

Does Base64 encoding encrypt my data?

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string to get the original content. It provides zero security. If you need to protect data, use actual encryption before encoding it.

What is the difference between Base64 and URL encoding?

Base64 converts any data to a limited set of ASCII characters (A-Z, a-z, 0-9, +, /). URL encoding (percent-encoding) replaces specific characters with %XX hex values. They solve different problems. Base64 is for embedding arbitrary data as text. URL encoding is for making strings safe in URLs.

Does Base64 work with non-English text?

Yes. Our encoder handles UTF-8, so Chinese, Arabic, Japanese, accented characters, and emoji all encode and decode correctly. The key is using a tool that properly handles the UTF-8 conversion step before Base64 encoding.

How much larger is Base64 than the original?

About 33% larger. Every 3 bytes of input become 4 bytes of Base64 output. A 1 KB string becomes roughly 1.33 KB when encoded. Plus padding characters (=) at the end if the input length is not divisible by 3.

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How Base64 Encoding Works

Base64 takes every 3 bytes of input and converts them into 4 characters from a 64-character alphabet: A-Z (26), a-z (26), 0-9 (10), + and / (2). The equals sign = is used for padding when the input length is not evenly divisible by 3.

Step by step for "Hi":

H = 72, i = 105 in ASCII
Binary: 01001000 01101001
Split into 6-bit groups: 010010 000110 1001
Pad the last group: 010010 000110 100100
Map to Base64 alphabet: S, G, k
Add padding: SGk=

Result: "Hi" encodes to "SGk="

Common Encoding Examples

Original Text	Base64 Encoded	Size Increase
Hello World	SGVsbG8gV29ybGQ=	11 → 16 chars (+45%)
user:password	dXNlcjpwYXNzd29yZA==	13 → 20 chars (+54%)
{"key":"value"}	eyJrZXkiOiJ2YWx1ZSJ9	15 → 20 chars (+33%)
https://example.com	aHR0cHM6Ly9leGFtcGxlLmNvbQ==	19 → 28 chars (+47%)

When to Use Base64 Encoding

Embedding Data in JSON

JSON does not support binary data. If you need to include a file, image, or binary blob in a JSON payload, Base64-encode it first. The receiving end decodes it back to binary.

HTTP Basic Authentication

The HTTP Authorization header for Basic auth expects username:password encoded as Base64. This is why you see headers like Authorization: Basic dXNlcjpwYXNzd29yZA==. Remember: this is encoding, not encryption. Always use HTTPS with Basic auth.

Data URIs in HTML/CSS

You can embed small images or fonts directly in HTML or CSS using data URIs: data:image/png;base64,iVBORw0KGgo.... This eliminates an HTTP request at the cost of a larger HTML file. Good for tiny icons, bad for large images.

Config Files and Environment Variables

Kubernetes secrets, CI/CD variables, and many cloud platforms store sensitive values as Base64. You encode when setting the value, and the system decodes when using it.

Base64 Encoding in Code

JavaScript: btoa("Hello") → "SGVsbG8="
Python: import base64; base64.b64encode(b"Hello").decode()
Linux/Mac: echo -n "Hello" | base64
PowerShell: [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes("Hello"))

Note: JavaScript's btoa() does not support UTF-8 characters directly. You need to encode to UTF-8 first. Our browser tool handles this automatically.

Base64 Is Not Encryption

This is the most common misunderstanding. Base64 does not protect your data. Anyone can decode it. If you see a password stored as Base64 in a config file, that password is effectively in plain text. For actual security, use proper encryption, then optionally Base64-encode the encrypted output for safe transport.

Related Encoding Tools

Different encoding for different situations: URL Encoder for making strings URL-safe, HTML Entity Encoder for escaping HTML special characters, Hash Generator for creating one-way checksums (MD5, SHA-256).