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Base64 Text Encoder & Online Decoder Tool

Safely transform your text strings into URL-friendly ASCII format. Our free Base64 encoder and decoder provides instant, secure data transformation for developers and IT professionals.

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The Developer's Guide to Base64

When you're dealing with strict data transfer protocols, moving raw binary data or special characters can break your JSON payload. Base64 encoding solves this by transforming strings into a uniform, URL-safe format.

How to Use This Tool

  1. Step 1: Select Direction - Choose whether you want to Encode text to Base64 or Decode strings back to plain text.
  2. Step 2: Input Data - Enter your source content into the input field for immediate processing.
  3. Step 3: Copy Transformation - Grab your encoded or decoded result instantly for use in your code or protocols.

Deeper Dive

Want to learn how Base64 encoding works bit-by-bit, data URIs, and why it is NOT encryption?

Read the full guide

How Base64 encoding works

Base64 turns binary data or text into plain letters, digits, plus and slash characters, so it can travel through systems that only handle text, such as email, JSON and URLs. Every 3 bytes of input become 4 characters of output, so encoded data is about one third larger. If the input length is not a multiple of 3, one or two equals signs are added at the end as padding.

Encoding is not encryption. Anyone can decode Base64 in a second, so never use it to hide passwords or personal data. Text is first converted to bytes, normally using UTF-8, so characters outside basic English, such as é or emoji, take more than one byte each.

Worked examples

Man

  • Man encodes to TWFu
  • 3 bytes in, 4 characters out, no padding.

Hi

  • Hi encodes to SGk=
  • 2 bytes in, so one equals sign of padding is added.

Decoding

  • TWFu decodes back to Man.

Tips and common mistakes

  • Common uses: embedding small images in web pages as data URLs, attaching files in email, and sending binary data inside JSON.
  • If decoding fails, check for missing padding, extra spaces or line breaks, or the URL-safe variant, which uses - and _ in place of + and /.
  • Do not Base64-encode large files just to store them; the size grows by about 33%.

Frequently Asked Questions

Representing binary data in ASCII format, commonly used in JSON or HTML data transfers.
No, Base64 is NOT encryption. It is a data format translation and is easily reversible.
No. All encoding and decoding happens locally in your browser for maximum privacy.

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