Base64 Encoder & Decoder
Encode and decode Base64 strings instantly — fully UTF-8 aware
What is Base64 Encoder & Decoder?
Base64 is an encoding scheme that converts binary or text data into a string of 64 printable ASCII characters. It is one of the most fundamental encodings in web development, used daily in authentication headers, data URIs, email attachments, and API payloads. The core problem it solves is simple: many protocols — HTTP headers, JSON fields, email bodies — are text-only and cannot carry raw binary data safely. Base64 encodes that binary into a portable text string that survives any transmission channel intact. Our free Base64 Encoder & Decoder lets you instantly convert any text string into Base64 and decode any Base64 string back to its original form. It fully supports multi-byte UTF-8 characters including accented letters, Arabic, Chinese, Japanese, Korean, and emoji — not just plain ASCII. Whether you are crafting HTTP Basic Auth headers, embedding a font in CSS as a data URI, inspecting an OAuth token, or passing binary data through a JSON API, this tool handles it instantly in your browser with complete privacy.
How to Use Base64 Encoder & Decoder
- 1
Paste Your Input
Enter the text you want to encode into Base64, or paste a Base64 string you want to decode. The tool accepts any UTF-8 text including emoji, non-Latin scripts, and special characters.
- 2
Encode or Decode
Click "Encode to Base64" to convert your text into a Base64 string. Click "Decode from Base64" to reverse a Base64 string back into the original human-readable text.
- 3
Copy the Result
Click the copy button to send the encoded or decoded output directly to your clipboard, ready to paste into a header, config file, code, or terminal command.
Use Cases
Building HTTP Basic Authentication Headers
The HTTP Basic Auth scheme requires credentials in the format username:password encoded as Base64, then sent as an Authorization header. Developers use this tool to manually craft or verify those headers when debugging API authentication flows with curl, Postman, or browser DevTools.
Embedding Images and Fonts as Data URIs
CSS and HTML support inline resources using data URIs in the format data:image/png;base64,<encoded-data>. This eliminates a separate HTTP request for small icons and loading spinners. Use the Base64 encoder to generate the encoded string, then paste it directly into your stylesheet or HTML tag.
Inspecting OAuth and JWT Components
OAuth access tokens and JWT headers/payloads are Base64url-encoded (a URL-safe variant). When an authentication flow misbehaves, decoding the token manually reveals the claims, expiry, and issuer fields without needing a separate JWT tool, giving you a quick sanity check on what your auth server actually sent.
Features
Full UTF-8 Support
Correctly encodes and decodes multi-byte UTF-8 characters — emoji, Arabic, Chinese, Japanese, accented Latin — not just the 7-bit ASCII that many online tools silently mangle.
Encode & Decode in One Place
Switch between encoding text to Base64 and decoding Base64 back to text without leaving the tool or opening a second tab.
Runs Entirely in Your Browser
No data is sent to any server. Safe to use with API keys, auth tokens, private credentials, and sensitive configuration strings.
One-Click Copy
Instantly copy the output to your clipboard with a single button — no manual selection needed.
Frequently Asked Questions
Base64 converts binary or text data into a portable string of 64 printable ASCII characters so it can be safely transmitted over text-only channels. Common uses: embedding images in CSS data URIs, HTTP Basic Authentication headers, passing binary payloads inside JSON fields, encoding email attachments in MIME format, and storing binary data in XML or HTML attributes.
No. Base64 is an encoding scheme, not encryption. Anyone with the Base64 string can decode it back to the original content in seconds. Never use Base64 as a security measure. For genuine security, use proper encryption (AES, RSA) or hashing (SHA-256 with salt). Base64 simply makes data text-safe, not private.
Base64 encodes data in groups of 3 bytes at a time, producing 4 output characters per group. When the input length is not a multiple of 3, padding characters (=) are added to the end to make the total output length a multiple of 4. One = means one byte of padding was needed; == means two bytes.
Standard Base64 uses + and / as its 63rd and 64th characters, which are not URL-safe. Base64url replaces + with - and / with _ so the encoded string can appear in a URL or filename without percent-encoding. JWT tokens use Base64url. This tool handles standard Base64; use the JWT Decoder tool for JWT-specific decoding.
Yes — Base64 increases the size of the encoded data by approximately 33%. Every 3 bytes of input become 4 characters of Base64 output. This is the trade-off for making binary data text-safe. For images embedded as data URIs, this size increase means larger HTML/CSS files, so it is best reserved for small assets under ~10 KB.
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