Base64 is a way to represent binary data using a limited set of printable characters, which makes it useful in data URLs, email formats, APIs, configuration files, and other text-based transports. This encoder/decoder converts between ordinary input and its Base64 representation.
It is important not to confuse encoding with security. Base64 is reversible and provides no confidentiality. Padding, character encoding, and whether the original content is text or arbitrary binary data can also affect the result, so exact workflows should use the same rules at both ends.
How to use this tool
How does the Base64 Encoder and Decoder work?
How to use Base64 Encoder and Decoder
- Choose whether you want to encode plain text or decode a Base64 string.
- Paste the exact input into the appropriate field.
- Run the operation and inspect the complete output.
- When exact reproduction matters, confirm the expected character encoding and whether padding is required.
- Do not treat Base64 as encryption or as protection for confidential data.
Technical reference
The Base64 alphabet, padding, and encoding rules are standardized in RFC 4648 – Base-N Encodings.
Examples
Encode ASCII text
Standard Base64 output is aGVsbG8=.
Decode Base64
The decoded UTF-8 text is Hello.
Padding
Standard Base64 may end with one or two = characters to pad the final 4-character block.
Unicode text
The exact Base64 depends on the byte encoding; UTF-8 should be used consistently when reproducing results.
Common use cases
- Encoding API credentials for formats that require Base64
- Decoding data URIs
- Inspecting email/MIME payloads
- Encoding small binary values
- Debugging Basic Authentication headers
- Converting UTF-8 text to Base64
Frequently asked questions
What is Base64 encoding?
Base64 represents binary data with a restricted set of printable ASCII characters. Standard Base64 maps every 3 input bytes to 4 encoded characters, with padding used when needed.
Is Base64 encryption?
No. Base64 is reversible encoding and provides no confidentiality. Anyone who has the encoded value can decode it.
Why does Base64 sometimes end with = characters?
The equals signs are padding used by standard Base64 when the input byte length is not a multiple of three.
Why can decoded text look corrupted?
The bytes may use a different character encoding, the input may be invalid or truncated, or the encoded data may represent a binary file rather than ordinary text.
Does Base64 make data smaller?
Usually not. Standard Base64 expands binary data by roughly one third before other transport overhead, so it is used for compatibility rather than compression.