Browser only
Normal conversion stays on this device.
Private conversion, ready when you are.
Base64 Decode & Encode Online
Decode Base64 or encode text instantly in your browser. Standard and URL-safe modes are ready.
Hover over the output to select it, then click once to copy.
Specialized workflows
More Base64 tools
Open a focused tool when the output needs more than plain text.
Base64 to Image Converter
Preview an image and inspect its MIME type, dimensions, size, and download.
Image to Base64 Converter
Create raw Base64, a data URL, HTML, or CSS from a local image.
Base64 Image Compressor
Resize or re-encode a Base64 image locally toward a smaller or target size.
Base64 Validator
Find illegal characters and inspect the alphabet, padding, and length.
Base64URL Decoder
Normalize Base64URL, compare standard Base64, and inspect JWT parts.
Decode Base64 File
Detect the real file type, preview safe formats, and download the original bytes.
Base64 to PDF Converter
Verify the PDF header, preview the document locally, and download it.
Data URL Decoder
Separate MIME type, charset, and payload, then preview or download safely.
Base64 to Hex Converter
Convert exact bytes between Base64 and hexadecimal in either direction.
JWT Decoder & Signature Verifier
Decode header and payload claims, inspect time validity, and optionally verify the signature.
JWT Encoder & Signer
Create a signed JWT from editable JSON using HMAC, RSA, RSA-PSS, or ECDSA.
A cleaner way to encode and decode Base64.
Short paths, clear controls, and browser-only processing before you paste a value.
Focused pages
Text, files, and history each get their own space.
Plain boundaries
Base64 is encoding, not encryption.
Private browser-only Base64 conversion
Decode Base64 is a focused utility for encoding text to Base64 and decoding Base64 back to readable text without sending your content to a server. The conversion runs in your browser using standard web APIs, so passwords, tokens, snippets, JSON payloads, and small files stay on your device. That local-first design is important for developers, analysts, support teams, and students who need a fast converter but do not want pasted data collected by an unknown backend.
Base64 is not encryption. It is an encoding format that represents bytes with printable ASCII characters. It is useful when binary data needs to travel through systems that expect text, such as email bodies, data URLs, HTTP headers, configuration files, and API examples. This tool makes that transformation easy while keeping the distinction clear: Base64 can make data portable, but it does not make sensitive information secret.
Standard Base64 and URL-safe Base64
The standard Base64 alphabet uses letters, numbers, plus signs, slashes, and optional equals padding. That format is common in MIME messages, basic authentication examples, certificates, and many command-line workflows. URL-safe Base64 replaces the plus sign with a hyphen and the slash with an underscore so the result can be placed in URLs, route parameters, JWT segments, and query strings with less escaping.
Auto detect mode tries to identify whether your input already looks like Base64. If the text is clearly plain language or contains characters outside the Base64 alphabet, the tool chooses encode mode. If the text can be decoded cleanly and round-trips to the same representation, the tool chooses decode mode. Manual encode and decode controls remain available because ambiguous short strings can exist in both worlds.
Text and file workflows
The text converter is designed for repeated work: paste input on the left, read the result on the right, switch URL-safe mode when needed, and copy the output. Character counts help you notice accidental whitespace or truncated values. Conversion history is stored locally in your browser so you can reuse recent transformations without creating an account or uploading anything.
The file converter supports small browser-side file workflows. You can turn a local file into a Base64 string for testing data URLs, API fixtures, or documentation examples. You can also paste Base64 and download it as a file when you need to inspect a payload. The size limit is intentionally conservative to keep the page responsive and avoid pretending that a browser tab is the right place for very large binary processing.
Readable errors instead of silent failure
Invalid Base64 should be obvious. This site does not silently return an empty result when decoding fails. A clear error message is safer because it tells you the input is incomplete, contains invalid characters, has broken padding, or does not represent valid UTF-8 text for the text decoder. Fast, loud feedback is better than a blank output box that could be mistaken for a valid decoded value.
For file output, the tool treats Base64 as bytes rather than text. That keeps binary use cases separate from text use cases and makes the code easier to reason about. The browser interface catches recoverable user errors and shows them near the relevant control; lower-level conversion modules remain small, pure, and testable.
Common uses for Base64
Developers use Base64 to embed small images in CSS or HTML, inspect API examples, decode JWT payload segments, prepare test fixtures, and move byte data through text-only systems. Support teams use it to understand customer-provided values without installing a desktop utility. Writers and educators use it to explain how binary-to-text encoding works with examples that can be copied, changed, and tested immediately.
For security-sensitive work, remember that Base64 is reversible by design. Do not treat an encoded value as protected. If a value must remain private, use real encryption, access control, and secret management. This site helps with encoding and decoding; it does not replace cryptography.
Help and FAQ
Can I decode Base64 files here?
Yes. Use the file section to turn a small local file into Base64, or paste Base64 and download it as a file. The work stays in the browser.
Is Base64 encryption?
No. Base64 is reversible encoding. It makes bytes safe for text systems, but it does not protect secrets.
Is my input sent to a server?
No. Normal text and small-file conversions run locally in this browser without uploading the input for processing.