Base64 Encoder / Decoder
Encodes text to Base64 and decodes Base64 back to plain text in the browser.
Runs entirely in your browser — nothing is uploaded or stored.
How to use this calculator
- Paste your text or Base64 string.
- Press Encode or Decode.
How it works
Base64 represents data using 64 safe characters (A–Z, a–z, 0–9, + and /). It's used to embed images, pass data in URLs and store binary in text formats. It makes data about 33% larger and is not encryption.
Worked example
"Hello". encodes to SGVsbG8=.
Common mistakes
- Pasting a data URL and expecting clean text — strip the data:...;base64, prefix first.
- Confusing Base64 with encryption — it only encodes data, it does not secure it.
Frequently asked questions
Does this upload my text anywhere?
No — encoding and decoding run entirely in your browser, so nothing you paste is sent to a server.
Is Base64 a form of encryption?
No. It re-encodes data into text so it survives transport; anyone can decode it, so never use it to protect secrets.
Is Base64 secure?
No — it's encoding, not encryption. Anyone can decode it.
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Cite this tool
Zerdly. (2026). Base64 Encoder / Decoder. Retrieved from https://www.zerdly.com/tools/base64-encoder-decoder/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.