Base64 Encoder / Decoder
Convert text to Base64 or decode Base64 back to text. Everything runs in your browser — your input is not sent anywhere.
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About Base64
Base64 represents binary data using 64 printable characters: A–Z, a–z, 0–9, +, and /. Output is grouped into 4-character blocks, with = used for padding when needed. Encoded data is typically about 4/3 the size of the original.
Notes
This tool encodes and decodes text using UTF-8 so that non-English characters work correctly. If you decode a value that is not valid Base64 (or not valid UTF-8 text), you’ll see an error message instead of a broken result.
How it works
Base64 encodes binary data (or text bytes) into ASCII characters so it can be safely transported in text-based systems.
Notes
- Encoding represents every 3 bytes as 4 Base64 characters (using A–Z, a–z, 0–9, +, / and = padding).
- This tool processes text as UTF-8 in your browser and does not send your data to a server.
Worked example
Hello, world! encodes to SGVsbG8sIHdvcmxkIQ== and decodes back to the same text.
For general information and convenience. Do not treat Base64 as encryption or a security measure.
How to use the Base64 Encoder / Decoder
It takes a few seconds, and every figure is calculated in your browser.
- Open the Base64 Encoder / Decoder and pick the mode you need.
- Type your values into the fields — nothing is uploaded or stored on a server.
- Read the result panel for the headline answer and the supporting figures.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Base64 Encoder / Decoder — frequently asked questions
How does the Base64 Encoder / Decoder work?
Base64 encodes binary data (or text bytes) into ASCII characters so it can be safely transported in text-based systems.
What assumptions and limitations should I know about?
This tool encodes and decodes text using UTF-8 so that non-English characters work correctly. If you decode a value that is not valid Base64 (or not valid UTF-8 text), you’ll see an error message instead of a broken result.
Can you walk through a worked example?
Hello, world! encodes to SGVsbG8sIHdvcmxkIQ== and decodes back to the same text.
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.