Base64 Encoder / Decoder
Encode text to Base64 and back — fully UTF-8 safe for umlauts, accents and emoji — or turn any file into a Base64 data URL. All locally in your browser.
Type in either field — conversion runs live in both directions.
How Base64 encoding works
Base64 maps every 3 bytes of data onto 4 characters from a 64-character alphabet (A–Z, a–z, 0–9, + and /), padding with = at the end. The output is ~33% larger than the input but survives every text-only channel — which is exactly the point.
Text mode
Both fields are live: type plain text to encode, or paste Base64 to decode. UTF-8 is handled correctly.
File mode
Choose any file and get its data URL — ready to paste as an image src in HTML or CSS.
Copy the result
One click on either side. Nothing is transmitted — encoding runs entirely on your device.
Where Base64 shows up — and one warning
You'll meet Base64 in data URLs for inline images, in email attachments (MIME), in HTTP basic auth headers, in JSON web tokens and in countless API payloads. The pitfall most simple tools have: the browser's native btoa() breaks on anything beyond single-byte characters, mangling umlauts and emoji. This encoder converts text to UTF-8 bytes first, so round-trips are lossless. And the warning worth repeating: Base64 is not encryption — it's a reversible encoding anyone can decode, never a way to hide secrets.
Frequently asked questions
What is Base64 used for?
Base64 represents binary data using only safe ASCII characters, so it can travel through text-only channels: embedding images in HTML/CSS as data URLs, email attachments, basic auth headers and API payloads.
Why do umlauts or emoji break in some Base64 tools?
The browser's raw btoa() function only handles single-byte characters. This tool encodes text as UTF-8 bytes first, so ä, é, 日本語 and emoji encode and decode correctly.
Is Base64 encryption?
No — it's an encoding, not encryption. Anyone can decode it instantly. Never use Base64 to protect secrets; it only makes data transport-safe.
What is a data URL?
A data URL embeds a file directly in text, like data:image/png;base64,… — usable as an image src in HTML or CSS without a separate file. The file tab generates it for any file you drop in.