Encoding

Base64 Encode

Encode plain text — including emoji and non-Latin scripts — into Base64, the format used to carry arbitrary data inside URLs, JSON, JWTs, data URLs, and HTTP headers without breaking the surrounding syntax.

Published February 20, 2024
Last reviewed June 28, 2026

Tool Summary Answer Block

This tool accepts structured input and returns deterministic output in the browser with no server upload.

Tool name: Base64 Encode
Input intent: Provide source content to transform, validate, or analyze.
Output intent: Receive normalized output suitable for copy, reuse, or debugging.
Example input: Hello, world
Example output: SGVsbG8sIHdvcmxk

URL-safe (base64url)

0characters0bytes0Base64 chars

Plain textDrop file

Base64 outputRead-only

Already have Base64? Switch to Base64 Decode

Tool Introduction

Tool Overview

Base64 represents arbitrary bytes using only 64 printable ASCII characters (A–Z, a–z, 0–9, plus + and /, with = padding). It exists because many transports — HTTP headers, JSON strings, URLs, email bodies — assume printable text and will mangle raw bytes. Encoding makes any input safe to drop into those contexts; decoding reverses it exactly. This encoder is UTF-8 safe, so accents, emoji, and CJK characters round-trip correctly instead of throwing the way a naive btoa() does. Toggle URL-safe to emit the base64url alphabet (- and _ instead of + and /, no padding), which is what JWTs and query-string parameters use. Everything runs locally in your browser, so even sensitive text never leaves your device. Remember: Base64 is encoding, not encryption — anyone with the string can decode it.

Use Cases

Embed an image, font, or small file inline as a data: URL in CSS or HTML
Put binary or special-character data inside a JSON field or HTTP header safely
Build the header and payload segments of a JWT (base64url)
Encode credentials for an HTTP Basic Authorization header
Move a config blob through a system that only accepts plain ASCII text

Input/Output Examples

Standard Base64 — three input bytes map to four output characters.

Input Intent

Hello, world

Output Intent

SGVsbG8sIHdvcmxk

UTF-8 safe: accents and emoji are encoded byte-for-byte.

Input Intent

café 👋

Output Intent

Y2Fmw6kg8J+Riw==

base64url swaps + / for - _ and drops = padding.

Input Intent

subjects?value=a/b+c (URL-safe)

Output Intent

c3ViamVjdHM_dmFsdWU9YS9iK2M

FAQ

Does Base64 encrypt or secure my data?+

No. Base64 is a reversible encoding, not encryption. Anyone with the Base64 string can decode it in seconds, so never use it to hide passwords or secrets.

Why is the output about a third larger than the input?+

Base64 packs every three bytes of input into four output characters, so the encoded text grows by roughly 4/3 (about 33% larger), plus padding.

What is the difference between Base64 and base64url?+

Standard Base64 uses + and / and pads with =, which can break inside URLs and filenames. URL-safe base64url replaces + and / with - and _ and omits padding, so it is safe in query strings, paths, and JWTs.

Can it handle emoji and non-English text?+

Yes. The text is encoded as UTF-8 first, so emoji, accented letters, and scripts like Devanagari, Arabic, or Chinese all encode and decode correctly.

Is my text uploaded anywhere?+

No. Encoding runs entirely in your browser, so your text never leaves your device.