Base64 Decoder
Paste a Base64-encoded string and get the original text back. Supports UTF-8 and Unicode. Processed entirely in your browser.
Tip: Press Ctrl+Enter to decode.
Base64 decoding vs. decryption
Base64 is not encryption. It is an encoding format — a way of representing binary data as printable text. Anyone who has the Base64-encoded string can decode it back to the original content without any key or password.
What is Base64URL?
JWT tokens and some other systems use Base64URL, a variant that replaces + with - and / with _, and omits padding. This tool handles standard Base64; for JWT payloads use the JWT Decoder instead.
Common use cases
- Reading API responses — some APIs return binary data (e.g. file content) Base64-encoded inside JSON fields.
- Inspecting email attachments — MIME-encoded attachments can be decoded to retrieve the original file content.
- Decoding data URIs — extract the raw image or font data from a
data:...;base64,URI.
Frequently Asked Questions
Why does my decoded Base64 text show gibberish or broken symbols?
This usually means the original encoded data was a binary file (such as an image, PDF, audio, or compiled bytecode) rather than UTF-8 plaintext, or was encoded with a legacy charset.
What causes 'Invalid character or padding' decode errors?
This occurs when the input contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /) or corrupted padding length. Our tool automatically cleans whitespace and repairs missing padding.
Can I decode sensitive tokens or API credentials safely?
Yes. Decoding executes 100% inside your local browser memory using client-side JavaScript. Nothing is sent over the network or saved in server logs.
How can I decode Base64 from the command line?
On Linux and macOS: `echo 'SGVsbG8=' | base64 --decode`. On Windows PowerShell: `[System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String('SGVsbG8='))`.
What is the difference between Base64 and Hex (Base16)?
Hexadecimal (Base16) uses 16 characters (0–9, a–f) and doubles data size (100% expansion). Base64 uses 64 characters and is significantly more compact, adding only ~33% overhead.
Can this tool decode Base64URL strings?
Yes. Utility Hub automatically detects and converts URL-safe characters (`-` and `_`) into standard Base64 characters (`+` and `/`) prior to decoding.