Base64 Encoder & Decoder

Encode text to Base64 or decode it back to text instantly — with URL-safe mode, file encoding, and full Unicode support. Nothing leaves your browser.

Convert

Results update live as you type.

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Input chars
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Input bytes (UTF-8)
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Output chars
100% private

Encoding happens locally in your browser with JavaScript. Your text and files are never uploaded anywhere.

No signup

Convert as much text as you like, instantly — no account, no email, no limits.

Free forever

UTF-8 safe encoding, URL-safe mode, file support, and auto-detect — all free, always.

How to use

  1. 1
    Pick a mode

    Choose Encode to turn text into Base64, Decode to turn Base64 back into text, or Auto-detect to let the tool decide.

  2. 2
    Enter your input

    Type or paste text into the input box — or pick a file to encode it to Base64. The output updates live as you type.

  3. 3
    Copy or download the result

    Use Copy output for the clipboard or Download output to save it as a .txt file. Use Swap to flip the result back into the input.

Features

Live conversion

The output updates on every keystroke — no buttons to press, no waiting.

UTF-8 safe

Uses TextEncoder and TextDecoder, so emoji, accented characters, and non-Latin scripts encode correctly — unlike plain btoa().

URL-safe mode

Toggle the URL-safe alphabet to get output with – and _ instead of + and /, safe for URLs and filenames.

File encoding

Pick any file — an image, a document, anything — and get its Base64 representation instantly, right in the page.

Auto-detect mode

Paste anything and the tool figures out whether it is text to encode or Base64 to decode.

Char and byte counts

See input characters, UTF-8 byte size, and output length at a glance.

Frequently asked questions

What is Base64?
Base64 is a way of representing binary data using only 64 safe text characters (A–Z, a–z, 0–9, +, /, and = for padding). It is commonly used to embed images in code, pass tokens in URLs and APIs, and store binary data in text formats like JSON.
Why do I get an “invalid Base64” error?
The input contains characters outside the Base64 alphabet, or its length is not a multiple of 4 after padding. Double-check for typos, stray spaces, or missing padding characters (=) at the end — or switch to Auto-detect mode.
What is URL-safe Base64?
Standard Base64 uses + and /, which have special meanings in URLs. The URL-safe variant swaps them for – and _. Turn on the URL-safe toggle when your output will live in a URL, a filename, or a JWT token.
Does it support Unicode and emoji?
Yes. This tool encodes with the UTF-8 byte representation (TextEncoder/TextDecoder), so any character — Arabic, Urdu, Chinese, emoji — round-trips correctly. Plain btoa() breaks on these; this tool does not.
Why is Base64 output longer than the input?
Base64 packs 3 bytes of data into 4 characters, so output is roughly 33% larger than the input. That is the trade-off for a text-safe representation.
Is it safe to encode passwords or private files here?
Yes — everything runs locally in your browser with JavaScript. Your text and files never leave your device. Note that Base64 is an encoding, not encryption: anyone can decode it, so never treat it as a way to hide secrets.
Is this tool really free?
Yes — free and unlimited, with no signup. It runs entirely in your browser, so there is nothing to pay for.

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