Base64 Encode / Decode
Encode text to Base64 or decode Base64 to text.
How to encode or decode Base64
Choose Encode to convert plain text into Base64, or Decode to turn a Base64 string back into readable text. Paste your input, drag in a text file, use history for recent values, then copy the output when it appears.
The tool handles UTF-8 text, so normal words, symbols, and many non-English characters round-trip correctly. If decoding fails, check whether the input has missing padding, line breaks from an email client, URL-safe characters, or extra whitespace copied around the encoded value.
Common Base64 workflows
Developers use Base64 when binary or structured data needs to travel through a text-only channel. Common examples include data URIs in HTML or CSS, email MIME attachments, API fixtures, authorization headers, encoded config values, and quick debugging of values copied from logs.
For JWTs, use the JWT Decoder instead of manually decoding each segment, because JWT uses Base64URL and adds token-specific claims such as exp, aud, and iss.
Know what Base64 does not do
Base64 is encoding, not encryption. Anyone can decode it, so it should not be used to hide secrets, passwords, tokens, or private customer data. If you need confidentiality, use a real encryption method before encoding the encrypted bytes for transport.
Base64 also increases size by about one third. It is useful for compatibility with text systems, but it is not a compression step.
Private browser-side conversion
Encoding and decoding happen inside your browser. FastDevTool does not upload the input, store the output, or send the text to an external API.
That makes the page convenient for local debugging, build scripts, sample payloads, and temporary snippets. Still, avoid sharing encoded values that contain secrets, because Base64 can be reversed instantly by anyone with a decoder.
Related Tools
Frequently Asked Questions
What is Base64 encoding?
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Base64 is a binary-to-text encoding scheme that converts binary data into a string of ASCII characters. It uses 64 printable characters (A-Z, a-z, 0-9, +, /) to represent arbitrary byte sequences, making binary data safe to include in text-based formats like JSON, XML, emails, and URLs.
Why is Base64 used?
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Base64 is used when you need to transmit binary data over channels that only support text. Common use cases include embedding images in HTML or CSS as data URIs, encoding file attachments in email (MIME), storing binary data in JSON APIs, and passing binary tokens in HTTP headers.
Does Base64 compress data?
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No — Base64 encoding actually increases data size by approximately 33%. Every 3 bytes of input become 4 Base64 characters. It is purely an encoding scheme for compatibility, not a compression algorithm. If you need smaller data, compress it first (e.g., with gzip) before encoding.
What is the difference between standard Base64 and URL-safe Base64?
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Standard Base64 uses '+' and '/' characters which have special meaning in URLs. URL-safe Base64 replaces '+' with '-' and '/' with '_' so the encoded string can be safely used in URLs and filenames without percent-encoding. This tool uses standard Base64.
Can Base64 encode any type of data?
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Yes. Base64 can encode any binary data — text, images, audio, executables, or any file type. This tool focuses on text encoding using UTF-8. To encode binary files, you would typically use a command-line tool or a programming library that handles raw bytes.