Base64 Encoder & Decoder - Online Tool

Base64 is used wherever binary data must travel through text-only systems. Common uses include embedding images directly in HTML or CSS as data URIs, encoding email attachments in MIME format, transmitting binary payloads in JSON APIs, storing binary data in XML, and encoding credentials in HTTP Basic Authentication headers. It is also widely used in JWTs (JSON Web Tokens) to encode the header and payload.

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly without a key — there is no secret involved. Encryption transforms data so only authorized parties can read it. Base64 simply changes how data is represented. Treating Base64 as a security measure is a common and dangerous mistake. If you need to protect data, use proper encryption algorithms like AES.

Yes — any valid Base64 string can be fully decoded back to its original binary data. Base64 is completely reversible, unlike hashing. However, the decoded output may be raw binary rather than readable text depending on the original input. If the source was a text string encoded as UTF-8, the decoded result will be readable. If it was a binary file, the output will be binary data.

Standard Base64 uses + and / characters, which have special meaning in URLs. Base64URL is a URL-safe variant that replaces + with - and / with _, and typically omits padding = characters. Base64URL is used in JWTs, OAuth tokens, and anywhere Base64 data appears in URLs or filenames. Our tool uses standard Base64 encoding.

Base64 encodes data in groups of 3 bytes into 4 characters. When the input length is not a multiple of 3, padding characters (=) are added to complete the final group. One = means the last group had 2 bytes; == means it had 1 byte. Padding ensures the encoded string length is always a multiple of 4, which simplifies decoding.