Yirinhana Tools

简体中文 · English · Español · Português · 日本語 · Deutsch

Base64 encode / decode

Base64 encode / decode. Transform, inspect and copy your data. Your files stay on this device. Processing happens in your browser.

Enable JavaScript to use the tools. Files are processed in your browser.

How to use it

To encode text, type or paste it and press Encode.

To decode, paste a Base64 string and press Decode. If the result is text it is shown; if it is binary data, such as an image, a download link appears.

To encode a file, choose it under Encode a file; tick as data URL to get a string you can paste into HTML or CSS.

What is Base64?

Base64 represents binary data using 64 safe characters: A–Z, a–z, 0–9, plus and slash, with equals signs as padding. Every 3 bytes of input become 4 characters, so encoded data is about 33% larger. It is used wherever binary data must travel through a channel designed for text, such as email attachments (MIME), JSON payloads, data URLs and HTTP Basic authentication headers.

Base64 is not encryption

Anyone can decode Base64 instantly, so it provides no secrecy at all. Do not use it to hide passwords or personal data. If a system asks you to send a key or token in Base64, treat the encoded string exactly as carefully as the original secret.

Text encoding and URL-safe Base64

Text is converted to UTF-8 bytes before encoding, so accented letters, Chinese characters and emoji round-trip correctly. The URL-safe variant from RFC 4648 replaces plus and slash with minus and underscore and drops padding, which is what JSON Web Tokens and many web APIs use. The decoder accepts both variants, ignores spaces and line breaks, and strips a data: prefix if one is pasted.

Privacy and size

The input is processed in this browser, without sending it to a conversion server. Pasted UTF-8 text and imported files are limited to 10 MiB each; complex data may fail sooner because memory and parser limits also apply. Page and script loading, advertising or analytics requests are separate; see Privacy. Downloaded results remain on your device.

Related tools

Unix timestamp converter

JSON to CSV converter

CSV to JSON converter

URL encode and decode

All converters

Frequently asked questions

Is Base64 secure?

No. It is an encoding, not encryption, and anyone can reverse it.

Why is the decoded text garbled?

The original data may not be UTF-8 text. When the bytes are not valid UTF-8, the tool offers them as a file download instead.

What is the difference between Base64 and Base64URL?

Base64URL uses - and _ instead of + and / and usually omits = padding, so it can be used in URLs and file names.

Are my files uploaded?

This converter does not upload the selected file or input for processing. That does not mean the website makes no network requests; see Privacy for page, advertising and analytics traffic.

Related tools