CONVERT.02 BASE64

Base64 Encode / Decode

Type plain text in the left editor to encode, or paste Base64 in the right editor to decode.

TXT

Plaintext

B64

After Encoding

§ 01

How to Use the Base64 Encode/Decode Tool

Enter Text

Type any text you want to encode in the left editor, or paste encoded ciphertext in the right editor.

Real-time Encode/Decode

The encoded/decoded result appears instantly on the other side. Click the copy button above either editor to copy the content to your clipboard.

§ 02

FAQ

Q1What is Base64 encoding?

Base64 is an encoding scheme that represents binary data using 64 printable characters. It is commonly used to transmit or store binary data or special characters in text-based environments such as email, XML, and JSON, ensuring data is not accidentally modified or truncated during transmission.

Q2Is Base64 a form of encryption? Is it secure?

No, Base64 is definitely not an encryption algorithm — it is merely a data encoding method. Anyone with Base64-encoded data can easily decode it back to its original content. Therefore, never use Base64 to "encrypt" passwords or other sensitive information.

Q3Will my data be uploaded?

No. All data on this tool site is processed locally in your browser — no user data or information is ever uploaded or saved.

Q4Why is Base64 output longer than the input?

Base64 encodes every 3 bytes into 4 characters, resulting in roughly a 4/3x increase, about 33% overhead. For example, 3 bytes "abc" becomes 4 characters "YWJj".

Q5What is the difference between Base64, Base64URL, and Base32?

Base64 uses +, /, and = padding and is the most common standard. Base64URL replaces + with -, / with _, and strips = padding, making it safe for URLs and filenames. Base32 uses 32 characters (A-Z, 2-7), primarily for secret keys and verification codes, with lower encoding efficiency than Base64.

Q6How can I tell if a string is Base64-encoded?

Look for these signs: only A-Z, a-z, 0-9, +, /, = characters; length is a multiple of 4; = only appears at the end, at most 2. However, matching these rules does not guarantee it is Base64 — it could be another encoding or a random string. Always try decoding to verify.

§ 03

Why Choose This Tool

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Real-time Bidirectional Sync: No buttons needed. Encoding and decoding happen simultaneously as you type — the only online Base64 tool with true real-time bidirectional conversion.

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Full UTF-8 Support: Handles Chinese, Japanese, Korean, Emoji, and all multi-byte characters flawlessly, unlike traditional ASCII-only Base64 tools.

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100% Data Privacy: All encoding and decoding happens locally in your browser. No data is ever uploaded to any server. Works offline too.

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Zero Ads, Zero Trackers: Clean, focused, distraction-free experience.

§ 04

Common Base64 Use Cases

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Data URIs: Embed small images or fonts directly into HTML/CSS as Base64 to reduce HTTP requests.

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API Authentication: HTTP Basic Auth transmits credentials as Basic base64(username:password).

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JWT Tokens: The payload section of JSON Web Tokens uses Base64URL encoding.

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Email Attachments: The MIME standard encodes binary email attachments using Base64.

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Configuration Files: Store binary data as plain text within JSON, XML, or YAML configs.

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Data Transport: Safely transmit binary data through protocols or systems that only support text.

§ 05

How Base64 Encoding Works

Base64 splits every 3 bytes (24 bits) of binary data into 4 groups of 6 bits, then maps each 6-bit value to one of 64 printable characters (A-Z, a-z, 0-9, +, /). If the input byte count is not divisible by 3, = characters are used as padding. This is why Base64 output length is always a multiple of 4, and may end with 1 to 2 equals signs.