Base64 Encode Online

Q: What is Base64 encoding?

Base64 encoding is a method of converting binary data into ASCII text using a set of 64 characters: uppercase letters (A-Z), lowercase letters (a-z), digits (0-9), plus (+), and forward slash (/). It is commonly used to transmit binary data over text-based protocols such as email or HTTP, ensuring the data remains intact during transfer without corruption.

Q: Does Base64 encoding provide encryption?

No. Base64 is encoding, not encryption, and provides no security at all. Anyone can decode a Base64 string back to the original in seconds, because the process is deterministic and uses no secret key. If you need to protect sensitive data, use proper encryption such as AES or RSA. Base64 only makes binary data safe to store and transmit as text — it never hides it.

Q: Why is the Base64 output larger than my input?

Base64 represents every 3 bytes of input as 4 ASCII characters, so the output is always about 33% larger than the original data. That overhead is the price of making binary data safe to travel through text-only channels. Because of this, Base64 is a poor choice when size matters — it is not compression, and you should not Base64-encode data simply to store it.

Q: Can I encode files with this tool?

Yes. Drag and drop a text file onto the input area, or click Import from File to select one. The file's contents are read and encoded to Base64 automatically. All processing happens in your browser, so your files are never uploaded to any server.

Q: What is the difference between standard and URL-safe Base64?

Standard Base64 uses + and / as two of its characters, but both have special meaning in URLs and are not allowed in filenames. URL-safe Base64 solves this by replacing + with - (hyphen) and / with _ (underscore), and often omits the trailing = padding. If you plan to put a Base64 string in a URL, query parameter, or filename, convert it to the URL-safe variant. This tool flags when your output contains + or / so you know conversion is needed.

Q: How are non-English characters and emoji handled?

This tool encodes text as UTF-8 first, then applies Base64, so accented letters, non-Latin scripts, and emoji all encode correctly. Note that multi-byte characters take more than one byte each — for example an emoji is typically 4 bytes — so a short string with emoji can produce a longer Base64 output than its character count suggests.

Encode text and files to Base64 format instantly. Convert any string or file content into a Base64-encoded representation for safe data transmission.

Encode Decode

Text to Encode (0 chars)

Base64 Encoded Result (0 chars)

All encoding happens locally in your browser. No data is sent to any server. Your text and files remain completely private.

What It Does

Base64 encoding turns any data — text, JSON, images, whole files — into a string made of just 64 plain ASCII characters (A-Z, a-z, 0-9, + and /). It exists so binary or special data can travel safely through systems that only expect text, such as email, URLs, JSON payloads and HTTP headers, without being corrupted along the way. The trade-off is size: Base64 represents every 3 bytes as 4 characters, so the encoded output is always about a third larger than the original. This tool encodes your text (as UTF-8, so emoji and non-English characters work) and shows you the result along with how much it grew and whether it is safe to drop into a URL. One thing to be clear about: Base64 is encoding, not encryption. It hides nothing — anyone can decode it — so never use it to protect secrets.

When to Use It

You need to embed an image, font or small file directly inside HTML, CSS or JSON as a data URI instead of linking to a separate file.
You are building an HTTP Basic Authentication header, which requires the username and password to be Base64-encoded.
You need to store binary or special-character data inside a text-only field — a config file, environment variable, JSON value or database column.
You are preparing a token or payload (for example the parts of a JWT) and need the data in a compact, text-safe form.

Worked Examples

Hello, World!

A 13-character string encodes to "SGVsbG8sIFdvcmxkIQ==" — 20 characters. The trailing == is padding that makes the length a multiple of four, and you can already see the ~33% size growth.

{"role":"admin","active":true}

Encoding a small JSON object produces the kind of compact, text-safe token you see inside JWT payloads and API requests. Decode it back any time with the Base64 Decode tool.

Café ☕ in Zürich

The accented é and the emoji are multi-byte in UTF-8, so this 16-character string is more bytes than it looks. The encoder handles UTF-8 correctly, which is why the Base64 output is longer than a plain-ASCII string of the same length.

Features

Real-time encoding as you type

Full Unicode (UTF-8) support for international characters and emoji

Size-overhead and URL-safety analysis of the output

File upload support for text files

Drag and drop file import

Copy encoded result with one click

Character count for input and output

Works entirely in your browser

No data sent to any server

How to Use

1. Type or paste your text in the input area. 2. The Base64-encoded result appears instantly below, with an analysis of its size and URL-safety. 3. Optionally drag and drop a file or click Import from File to upload a text file. 4. Click Copy to copy the encoded result to your clipboard. 5. Click Clear to reset the input and output fields.

Common Mistakes

Treating Base64 as encryption. It protects nothing — anyone can decode it instantly. Never Base64-encode a password or secret and assume it is safe.
Using it to save space. Base64 makes data about 33% larger, not smaller. It is the opposite of compression and should never be used to shrink data.
Dropping standard Base64 into a URL or filename. The + and / characters break URLs and are invalid in filenames — convert to URL-safe Base64 (- and _) first.
Forgetting about UTF-8. Encoding non-ASCII text without converting to UTF-8 first corrupts the data. This tool handles UTF-8 for you, but other libraries may not by default.

Frequently Asked Questions

What is Base64 encoding?

Does Base64 encoding provide encryption?

Why is the Base64 output larger than my input?

Can I encode files with this tool?

What is the difference between standard and URL-safe Base64?

How are non-English characters and emoji handled?