This Base64 encoder and decoder converts UTF-8 text to Base64 and back entirely in your browser — nothing is uploaded.
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Base64 Encoder & Decoder
Convert UTF-8 text to and from Base64 entirely in the browser.
Calculator
About this calculator
Formula notes
Base64 maps every 3 bytes to 4 characters from a 64-symbol alphabet, so output is about 33% larger than input.
Worked examples
- Example: “Hello” encodes to SGVsbG8=, matching the page default.
- Encoding the UTF-8 text 'Luna 2026' produces a Base64 string of 12 characters; decoding restores the original 9-byte ASCII text.
How to use it
- Choose encode or decode mode.
- Paste the text or Base64 string.
- Read the converted output instantly.
Frequently asked questions
Is Base64 encryption?
No. It is only an encoding — anyone can decode it, so never use it for secrets.
Why does output end with = signs?
Padding makes the length a multiple of 4 when the input is not a multiple of 3 bytes.
Limits and interpretation
- Base64 is reversible encoding, not encryption, hashing, authentication, or secure storage.
- Different systems may use URL-safe alphabets, omit padding, or interpret decoded bytes with a different character encoding.