100% Client-Side

Base64 Encoder

Encode text or binary data to Base64 — standard and URL-safe variants

Free Client-Side No Login No Storage
Loading tool...
Base64 Decoder Decode Base64 strings back to plain text or binary data URL Encoder Percent-encode URLs and query strings for safe transmission Hex Encoder Convert text to hexadecimal — useful for debugging and binary inspection Binary Encoder Convert text to binary representation — byte by byte

How to Use the Base64 Encoder

  1. Paste text or drag-drop a file into the input.
  2. The Base64-encoded output appears instantly.
  3. Toggle URL-safe mode to replace + and / with - and _ (safe for URLs and filenames).
  4. Copy or download the result.

What is Base64?

Base64 is an encoding scheme that converts binary data into ASCII text using 64 printable characters (A-Z, a-z, 0-9, +, /). It is not encryption — it is purely an encoding format.

Common uses

  • Email attachments — MIME encoding for binary files in email
  • Data URIs — embed images directly in HTML/CSS as base64 strings
  • API payloads — safely transmit binary data in JSON
  • JWT tokens — the header and payload sections are Base64URL encoded
  • Basic Auth — HTTP Basic Authentication encodes credentials as Base64

Note: Base64 increases data size by ~33%. It is not suitable for large files.

What is Base64 Encoding?

Base64 is an encoding scheme that converts binary data into ASCII text using 64 printable characters (A–Z, a–z, 0–9, +, /). It was designed for safely transmitting binary data over systems built to handle text, like email (MIME) and HTTP headers. Encoding increases data size by roughly 33 % but ensures safe transmission across any text-based channel.

Common Uses

  • Encoding images or files as data URIs in HTML/CSS (src="data:image/png;base64,…")
  • Sending binary data in JSON API payloads
  • HTTP Basic Auth header encoding (username:password → Base64)
  • Storing binary data in environment variables or config files
  • JWT token payloads are Base64URL-encoded

Frequently Asked Questions

Is Base64 the same as encryption?

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly — it provides no security. Use AES or RSA for actual encryption.

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

Standard Base64 uses + and / characters which have special meaning in URLs. URL-safe Base64 replaces + with - and / with _ so the output can be safely used in URLs and filenames without percent-encoding.

Why does my Base64 string end with = or ==?

The = characters are padding. Base64 encodes 3 bytes at a time into 4 characters. If the input length isn't divisible by 3, padding is added to make the output a multiple of 4 characters.

Notes from this implementation

Encoding, counted in bytes

Base64 maps every 3 bytes to 4 characters from A–Z, a–z, 0–9, +, and /. Padding with = fills a final group that was short. The text box is read as UTF-8, so é is two bytes and will not match a tutorial that encoded Latin-1.

Vector

hello
aGVsbG8=

URL-safe Base64, used in JWT segments, replaces + with - and / with _, and often drops the padding. This page’s standard encoder will not match a JWT segment until you apply that alphabet. The JWT decoder does that for you. Do not “encrypt” a password by Base64-encoding it; anyone can reverse the alphabet.