Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to readable text instantly. Supports UTF-8 and Base64URL with private browser-based processing.
Encode & Decode Base64
Convert UTF-8 text to Base64 or decode Base64 back to readable text. Standard Base64 and URL-safe Base64 are both supported.
Encode: Ctrl/Cmd + Enter
Decode: Ctrl/Cmd + Shift + Enter
Conversion Statistics
Compare the character and byte sizes of your source and processed data.
Input Characters
0
Input Bytes
0
Output Characters
0
Output Bytes
0
Standard Base64 vs Base64URL
The two formats encode the same type of byte data but use slightly different characters so Base64URL can be used more conveniently inside URLs and web tokens.
| Feature | Standard Base64 | Base64URL |
|---|---|---|
| Character 62 |
+
|
-
|
| Character 63 |
/
|
_
|
| Padding |
Commonly uses
=
|
Often omitted |
| Typical Use | General binary-to-text encoding | URLs, JWTs and web applications |
Base64 Example
Encoding changes the representation of data. It does not hide or encrypt it.
Original Text
SwiftVecto
Base64
U3dpZnRWZWN0bw==
UTF-8 and International Character Support
This tool converts text through UTF-8 bytes before encoding and reconstructs UTF-8 text after decoding.
This means you can correctly work with international characters such as:
£100
₵500
Café
世界
SwiftVecto
Private Browser-Based Base64 Processing
Text encoding and decoding are performed directly inside your browser.
- No file upload is required.
- Your text does not need to be sent to SwiftVecto's server.
- UTF-8 conversion and Base64 processing happen locally on your device.
- Generated results can be copied or downloaded directly from the browser.
Base64 is not encryption, so encoded secrets should still be treated as sensitive information.
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How to Encode and Decode Base64
Use the SwiftVecto Base64 Encoder / Decoder to convert text into Base64 or decode Base64 back into readable UTF-8 text. The tool also supports URL-safe Base64 for data that needs to be used safely inside URLs, tokens or web applications.
Overview
Base64 is a binary-to-text encoding method used to represent bytes using a limited set of printable characters. It is commonly used in web development, APIs, email systems, authentication tokens, configuration files, data URLs and many other technical formats. Base64 is useful when data needs to travel through systems that are designed primarily for text, but it is important to understand that Base64 is encoding rather than encryption. Anyone who obtains Base64-encoded data can normally decode it. This Base64 Encoder / Decoder provides a simple way to encode UTF-8 text, decode Base64, inspect encoded values and work with the URL-safe Base64 variant directly in the browser.
Benefits
How It Works
Choose whether you want to encode text or decode Base64.
Enter or paste the source content into the input area.
Choose standard Base64 or URL-safe Base64 where applicable.
When encoding, the input text is first represented as UTF-8 bytes.
Those bytes are converted into the Base64 representation.
When decoding, the Base64 characters are converted back into their original byte values.
The resulting bytes are interpreted as UTF-8 text.
Base64URL replaces characters that are less convenient inside URLs with URL-safe alternatives.
Base64URL may also omit the trailing equals-sign padding used by standard Base64.
The processed output can be copied, downloaded or cleared for another conversion.
How to Use This Tool
-
1Choose Encode or Decode.
-
2Enter your text or Base64 value in the input field.
-
3Select Standard Base64 or Base64URL.
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4Choose Encode when converting readable text to Base64.
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5Choose Decode when converting Base64 back into readable text.
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6Review the output and statistics.
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7Copy the result if you need to paste it into another application.
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8Download the output if you want to save it locally.
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9Use Clear to reset the tool and process another value.
Helpful Tips
- Remember that Base64 is encoding, not encryption.
- Do not use Base64 alone to protect passwords, secrets or confidential information.
- Use Base64URL when encoded values need to appear safely inside URLs or URL-based tokens.
- Standard Base64 commonly uses the characters + and /, while Base64URL replaces them with - and _.
- Base64 padding is represented with equals signs at the end of some encoded values.
- Some Base64URL implementations omit padding, so a decoder should handle both padded and unpadded input.
- Use UTF-8-aware encoding when working with international characters.
- Avoid naïve browser implementations that call btoa directly on Unicode text because they can fail with non-ASCII characters.
- When decoding, invalid characters or incorrect padding may indicate corrupted or incomplete Base64 data.
- A successful Base64 decode does not guarantee that the resulting bytes represent readable text.
- Binary files may also be represented using Base64, but this text-focused tool is intended primarily for text content.
- JWT headers and payloads use Base64URL rather than ordinary Base64.
- Long Base64 strings are typically larger than their original binary data because encoding adds overhead.
- Base64 encoding is commonly useful for transport compatibility rather than storage efficiency.
- Avoid pasting passwords, API secrets or private credentials into any unnecessary development workflow.
Common Uses
Encode API credentials or test strings during development.
Decode Base64 copied from an API response.
Convert UTF-8 text containing international characters into Base64.
Decode Base64 configuration values during troubleshooting.
Prepare URL-safe Base64 values for web applications.
Inspect Base64URL strings used inside JWT structures.
Encode small pieces of text for embedding inside JSON or XML.
Decode data copied from browser developer tools.
Compare standard Base64 and Base64URL representations.
Verify that a Base64 value can be decoded successfully.
Encode sample payloads while testing integrations.
Decode Base64 received from another programming language or application.
Worked Examples
The following examples demonstrate how this tool can be used in realistic scenarios.
Encoding Simple Text
Enter the text "SwiftVecto" and choose Encode. The tool converts the UTF-8 bytes representing that text into a Base64 string that can later be decoded back to the original value.
Decoding API Data
A developer receives a Base64 value inside an API response and wants to inspect its contents. Paste the encoded string, choose Decode and review the resulting UTF-8 text.
Encoding Unicode Text
Text such as "Hello 世界 £ € ₵" contains characters outside basic ASCII. The tool first converts the text into UTF-8 bytes before Base64 encoding it, allowing the original characters to be restored correctly during decoding.
Using Base64URL
A web application requires encoded data that will appear inside a URL. Selecting Base64URL produces the URL-safe variant, replacing characters such as + and / with - and _ and allowing padding to be handled appropriately.
Inspecting JWT Segments
JWT header and payload segments use Base64URL encoding. A developer can use Base64URL decoding to inspect an individual encoded segment, although the dedicated JWT Decoder is normally more convenient for complete JWT inspection.
Common Mistakes
Avoid these common mistakes to achieve the most accurate results.
- Assuming Base64 protects sensitive data from being read.
- Using Base64 as a replacement for encryption.
- Passing Unicode text directly to browser btoa without first converting it to bytes.
- Trying to decode Base64URL as strict standard Base64 without translating URL-safe characters.
- Rejecting valid Base64URL solely because its padding has been omitted.
- Adding or removing characters from an encoded value accidentally while copying it.
- Including spaces or line breaks that were not part of the original encoded value.
- Confusing Base64URL with URL percent encoding.
- Expecting every successfully decoded Base64 value to contain readable text.
- Using Base64 for large binary files when a more appropriate file-processing workflow would be better.
- Assuming Base64 reduces data size.
- Treating an invalid Base64 string as application data without validating it first.
- Sharing encoded credentials because the value looks unreadable.
- Confusing Base64 encoding with hashing.
- Assuming an encoded value cannot be reversed.
Glossary
Definitions of the most important terms used by this tool.
Base64
A binary-to-text encoding scheme that represents byte data using a set of 64 printable characters.
Encoding
The process of converting data into another representation so it can be stored or transferred in a particular format.
Decoding
The process of converting encoded data back into its original representation.
Base64URL
A URL-safe variation of Base64 that replaces characters such as + and / with - and _ and commonly omits padding.
UTF-8
A widely used character encoding capable of representing Unicode text from many languages and writing systems.
Byte
A unit of digital data consisting of eight bits. Base64 encodes binary byte data into printable characters.
Binary Data
Data represented as bytes rather than directly as readable text. Images, documents and other files are examples of binary data.
Padding
Equals signs added to the end of some standard Base64 values so the encoded output has the required length structure.
Unicode
A character standard designed to represent text from languages and symbol systems around the world.
ASCII
An older character encoding covering a limited set of English letters, numbers, punctuation and control characters.
Data URL
A URL format that can embed small pieces of data directly inside a URL, sometimes using Base64 encoding.
URL Encoding
A separate encoding mechanism used to represent special characters safely inside URLs. It should not be confused with Base64URL.
JWT
JSON Web Token, a token format whose compact representation commonly uses Base64URL for header and payload sections.
Reversible Encoding
An encoding method where the encoded data can be converted back into its original representation without requiring a secret key.
Encryption
A security process that transforms information so it cannot normally be read without the appropriate cryptographic key. Base64 is not encryption.
Hashing
A one-way transformation used for fingerprints, integrity checks and other purposes. Unlike Base64, hashing is not intended to be reversed.
Frequently Asked Questions
What is Base64?
Base64 is a binary-to-text encoding method that represents bytes using printable characters. It is widely used when binary or arbitrary byte data needs to pass through systems designed primarily for text.
What does a Base64 encoder do?
A Base64 encoder converts input bytes into the printable Base64 representation. For normal text, the text is first converted into bytes using a character encoding such as UTF-8.
What does a Base64 decoder do?
A Base64 decoder converts an encoded Base64 string back into its original bytes. When those bytes represent UTF-8 text, they can then be displayed as readable characters.
Is Base64 encryption?
No. Base64 is an encoding format and provides no meaningful confidentiality. Anyone who has the encoded value can normally decode it without a password or secret key.
Can Base64 be reversed?
Yes. Base64 is deliberately reversible. Valid Base64 data can be decoded back into the original bytes.
What is Base64URL?
Base64URL is a variation of Base64 designed to work conveniently in URLs and filenames. It replaces + with -, replaces / with _, and commonly omits equals-sign padding.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and / as part of its alphabet and may use = padding. Base64URL uses - and _ instead, making the encoded value easier to place inside URLs without additional escaping.
Why does Base64 sometimes end with = or ==?
The equals signs are padding used by standard Base64 when the original number of bytes does not divide evenly into the encoding groups. Depending on the input length, there may be no padding, one equals sign or two.
Can Base64URL omit padding?
Yes. Base64URL is commonly used without trailing equals-sign padding. A robust decoder can restore the required padding when necessary before decoding.
Can this tool encode Unicode text?
Yes. The tool is designed to encode UTF-8 text correctly, including characters such as accented letters, currency symbols and non-Latin scripts.
Why does JavaScript btoa sometimes fail with Unicode text?
The browser btoa function works with byte-oriented binary strings rather than arbitrary Unicode text. UTF-8 text should first be converted into bytes before Base64 encoding.
Can Base64 contain spaces?
The Base64 alphabet itself does not use spaces as encoded characters. Some systems may insert line breaks or whitespace when displaying long Base64 values, but such formatting may need to be removed before strict decoding.
Is Base64 smaller than the original data?
No. Base64 normally increases the size of binary data by roughly one third because each group of binary bytes is represented using printable text characters.
Why is Base64 used if it makes data larger?
Base64 is useful because it allows arbitrary bytes to be represented safely inside text-oriented systems such as email, JSON, XML, HTML and certain protocol fields.
Can Base64 be used for passwords?
Base64 should not be used as password protection because it is easily reversible. Password storage should use appropriate password hashing mechanisms, while confidential data should use suitable encryption.
Can I encode API keys using Base64?
You can encode text containing an API key, but the result is not protected. If a protocol specifically requires Base64, follow that protocol, but do not treat the encoded result as secret merely because it looks unreadable.
Does Basic Authentication use Base64?
HTTP Basic Authentication commonly represents the username and password pair using Base64. This is why Basic Authentication must be protected by HTTPS because Base64 itself does not provide encryption.
Does JWT use Base64?
JWT compact representations use Base64URL for their encoded sections. The dedicated SwiftVecto JWT Decoder is usually more convenient when inspecting complete JSON Web Tokens.
Can Base64 represent binary files?
Yes. Base64 operates on bytes and can therefore represent images, documents and other binary content. This particular tool focuses initially on text-based encoding and decoding.
Why does decoded Base64 sometimes look unreadable?
The decoded bytes may represent binary data rather than UTF-8 text, or the data may use a different character encoding. Successfully decoding Base64 does not guarantee that the result is human-readable text.
How do I know whether a string is valid Base64?
A validator can check the character alphabet, padding and structural requirements. However, a string that is structurally valid Base64 may still decode into meaningless bytes.
Does SwiftVecto upload the text I encode or decode?
The interactive Base64 Encoder / Decoder is designed to perform routine text encoding and decoding directly in your browser, so no file upload is required for normal use.
Is this Base64 Encoder / Decoder free?
Yes. SwiftVecto provides this online developer utility for encoding and decoding Base64 and Base64URL text.
Things to Know
- Base64 is an encoding mechanism and should not be considered a security control.
- The tool is designed to handle text using UTF-8 encoding.
- Standard Base64 may contain +, / and = characters.
- Base64URL uses - and _ instead of + and /.
- Base64URL commonly omits trailing equals-sign padding.
- Encoded output is generally larger than the original byte data.
- Decoded bytes may not always represent readable UTF-8 text.
- The initial version of this tool focuses on text rather than uploaded binary files.
- Normal interactive encoding and decoding is intended to happen locally inside the browser.
- Avoid treating Base64-encoded credentials or secrets as protected information.
Disclaimer
Base64 does not encrypt, secure or anonymise information.
Users should not rely on Base64 to protect passwords, API keys, personal information or other sensitive data.
A structurally valid Base64 value may still decode into binary, corrupted or application-specific content rather than readable text.
The tool is intended for development, debugging and general data-conversion purposes.
Users remain responsible for handling confidential information appropriately.
Official References
The following official resources were used when developing this tool and are useful for further reading.
RFC 4648 - Base-N Encodings
https://www.rfc-editor.org/rfc/rfc4648
MDN Web Docs - Window.btoa()
https://developer.mozilla.org/en-US/docs/Web/API/Window/btoa
MDN Web Docs - Window.atob()
https://developer.mozilla.org/en-US/docs/Web/API/Window/atob
WHATWG Encoding Standard
https://encoding.spec.whatwg.org/