Base64 Encoder / Decoder

Encode text to Base64 or decode Base64 strings back to plain text. Instant results, nothing leaves your device.

Plain text input

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How to use

Select Encode or Decode mode from the toggle.
Paste your text (to encode) or your Base64 string (to decode) into the input field.
The output appears instantly. Click Copy to copy the result to your clipboard.

Tips for best results

Decode before formatting JSON payloads. Many API responses use Base64-encoded JSON inside a wrapper object. Decode the Base64 value first, then paste the result into the JSON formatter to read the nested structure clearly.
Check for URL-safe variants. If you're decoding a JWT or URL parameter and the result is garbled, try switching to URL-safe mode, JWTs use - and _ instead of + and / in their Base64 payload sections, and that single character difference breaks standard decoding.
Generate strong secrets first, then encode. If you need to create an API key or token to Base64-encode, use the password generator to create a high-entropy random string before encoding it.
Encode data URIs for small inline assets. You can encode a small icon or logo and embed it directly in CSS or HTML as a data URI, useful for eliminating a network request for frequently-used assets. The QR code generator uses Base64-encoded data internally when exporting images for embedding.

Why use PixMidas

Both directions in one tool. Encode and decode with a single toggle, no switching between separate tools.
100% private. Processing uses JavaScript's native btoa() and atob(), nothing is sent to any server.
No account needed. Free and instant. Encoding runs locally on your device.

Frequently asked questions

What is Base64 encoding?

Base64 converts binary data into a string of 64 printable ASCII characters (A–Z, a–z, 0–9, + and /). Every 3 bytes of input produce 4 Base64 characters, making the output about 33% larger. This encoding makes binary data safe to transmit through text-only channels like HTTP headers, JSON payloads, XML and email. It is not a compression algorithm, the encoded output is always larger than the original input, so it's purely a format-safety mechanism, not a size reduction technique.

Is Base64 the same as encryption?

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly without any key or password, it provides no security or privacy whatsoever. Its only purpose is to make binary data safe to transmit as text in systems that only accept printable characters. Never use Base64 to hide or protect sensitive information; use proper encryption algorithms like AES for anything requiring confidentiality.

What is Base64 used for in web development?

Embedding small images directly in HTML or CSS as data URIs (src="data:image/png;base64,..."). Encoding binary attachments in email via MIME. Transmitting binary data in JSON API payloads where binary fields must be represented as strings. Storing API keys in environment variables. JWT (JSON Web Tokens) use a variant called Base64URL for their header and payload sections, decoding the payload exposes the claims without needing any secret key.

Why does my Base64 string fail to decode?

Common causes: missing padding characters (= or ==) at the end, characters outside the Base64 alphabet (most often from a URL-safe variant using - and _ instead of + and /), or the string was encoded multiple times. If decoding produces garbled output, the original data was likely binary (an image or file) rather than plain text. You can verify padding requirements by checking whether the string length is a multiple of four, valid Base64 strings always are.

What is Base64URL and how is it different?

Base64URL replaces + with - and / with _ so the encoded string can appear safely in URLs and JSON Web Tokens without percent-encoding. If you're working with JWTs, use Base64URL decoding rather than standard Base64 to avoid character set errors. The padding character = is also often omitted in Base64URL contexts, which is why some JWT decoders require you to add padding manually before parsing. Most authentication libraries handle this conversion automatically, but when inspecting JWT payloads manually this distinction matters.