How to Use the Base64 Encoder & Decoder
Select the "Encode" tab to turn plain text into a Base64 string, or the "Decode" tab to turn a Base64 string back into readable text. Type or paste your input, and the result updates instantly — no submit button needed.
To encode an image or small file as a Base64 data URI (handy for embedding icons directly in CSS or HTML without an extra HTTP request), switch to the "File" tab and drag your file in. The tool shows the resulting data URI and its character length, so you can judge whether inlining it is worth the payload size.
Because encoding and decoding both happen locally in your browser using native JavaScript functions, nothing you paste is ever sent to a server, which makes this safe to use with tokens, credentials, or private data while debugging APIs.
Common Use Cases
- API Debugging: Quickly decode Base64-encoded JWT tokens, API responses, or authorization headers to inspect their contents.
- Email Attachments: MIME-encoded email content uses Base64 — decode it to view the original message or attachment data.
- Data URIs: Embed small images, fonts, or SVGs directly in HTML or CSS by converting them to Base64 data URIs, reducing HTTP requests.
- Configuration Files: Some systems (like Kubernetes Secrets) store values as Base64. Use this tool to encode or decode those values easily.
Frequently Asked Questions
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What is Base64 encoding used for?
Base64 converts binary data (like images) into an ASCII string format. It is commonly used to safely transmit data over text-based protocols like HTTP or email.
Is Base64 a type of encryption?
No, Base64 is strictly a data encoding format. It provides zero cryptographic security and can be easily decoded by anyone.
Why do Base64 strings end with an equals sign (=)?
The equals sign is used as padding. Base64 processes data in 24-bit chunks; if the input data doesn't divide evenly, padding is added to complete the string.
Can Base64 reduce file size?
No, encoding data into Base64 actually increases the size of the original data by about 33% because it uses 4 text characters to represent every 3 bytes.
How do you decode Base64?
You can decode Base64 using online decoders or native programming functions (like atob() in JavaScript or base64_decode in PHP) to revert it to its original format.