Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text — both in one place. Runs entirely in your browser.
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Base64 is the encoding scheme that developers encounter constantly — in email attachments, HTTP Basic Auth headers, data URIs in CSS, JSON Web Tokens, and API payloads that must carry binary content. The algorithm maps every three bytes of input to four printable ASCII characters drawn from a 64-character alphabet (A–Z, a–z, 0–9, +, /), padding with = signs when the input length is not a multiple of three. This makes binary data safe to transmit through text-based channels that would otherwise corrupt it. Whether you are inspecting a JWT, embedding a small image in CSS, or debugging an API response, Base64 encoding and decoding are tools you reach for daily.
Most online tools force you to choose a page for encoding and a separate page for decoding. This combined tool removes that friction. Paste your text or Base64 string, click the direction you need, and your result appears instantly — all processing stays in your browser with no data sent anywhere.
Paste your text or Base64 string into the input panel.
Select "Encode" to convert to Base64, or "Decode" to convert back to text.
Copy the result from the output panel — conversion is instant.
What Is Base64 Encoding?
Base64 encoding converts arbitrary binary data — or any UTF-8 text — into a string that uses only 64 safe ASCII characters. The name comes from that alphabet size. Because the output contains no special characters beyond + / and =, it travels safely through systems that handle only printable text: email protocols (MIME), HTTP headers, XML attributes, and JSON fields. One common misconception is that Base64 is encryption — it is not. It is purely a representation change, and any Base64 string can be decoded by anyone who has the encoded output. For confidentiality, combine Base64 with actual encryption.
How to Use This Tool
Select Encode to convert plain text to Base64, or Decode to convert a Base64 string back to readable text. Paste your input into the left panel, then read the result in the right panel. Switch direction any time without navigating away — both modes share the same interface. The tool handles full UTF-8, including accented characters, emojis, and CJK scripts, converting them to the correct byte sequences before encoding.
Why Developers Use Base64 Daily
Base64 appears in more places than most developers realize. JWTs (JSON Web Tokens) use Base64url — a URL-safe variant — for their header and payload sections, so decoding the middle section of any JWT reveals its claims as plain JSON. Basic Auth headers encode credentials as Base64. Data URIs embed images, fonts, and other assets directly in HTML or CSS. Email clients encode attachments with MIME Base64. Having a fast, no-install, browser-local tool ready saves the context-switch of opening a terminal or searching for a trustworthy online converter every time you need a quick check.
Common Base64 Examples
The string "Hello, World!" encodes to "SGVsbG8sIFdvcmxkIQ==". The two trailing = characters are padding that aligns the output to a multiple of four characters. A JWT always has the form xxxxx.yyyyy.zzzzz — decode the yyyyy section to read the token's payload claims as plain JSON. Basic Auth sends "Authorization: Basic dXNlcjpwYXNz" where the value decodes to "user:pass". Data URIs look like "data:image/png;base64,iVBORw0KGgo…" — a complete image file encoded as a long Base64 string.
Frequently asked questions
What is Base64 and what is it used for?
Base64 is an encoding scheme that converts binary data or UTF-8 text into a string of printable ASCII characters. It is used in JWTs, HTTP headers, data URIs, email attachments, and anywhere binary data must travel through text-based channels without being corrupted.
Does encoding and decoding happen in my browser?
Yes. All processing happens locally in your browser. No data is sent to our servers or to any third party.
Is Base64 the same as encryption?
No. Base64 is a representation format, not encryption. Any Base64 string can be decoded without a password. To protect sensitive data, use real encryption in addition to Base64.
Does this tool support special characters and emojis?
Yes. The tool handles full UTF-8 text, including accented characters, emojis, and non-Latin scripts such as Chinese or Arabic.
What is the difference between standard Base64 and Base64url?
Base64url replaces + with - and / with _ to make the string safe for use in URLs and filenames. This tool uses the standard Base64 alphabet (RFC 4648).