Base64 Decode
Runs in your browser — your data is never uploaded.
Paste a Base64 string and get the original text back instantly. OkConverter validates the input, tolerates line-wrapped strings (as produced by email clients and CLI tools), and decodes the result as UTF-8 so international text comes out intact. Decoding happens entirely in your browser — encoded credentials or tokens are never uploaded anywhere.
0 characters · runs entirely in your browser
How to use Base64 Decoder
- 1
Paste the Base64 string into the box — line breaks and spaces are fine.
- 2
Click “Decode” to convert it back to readable text in your browser.
- 3
Copy the decoded text, or download it as a .txt file.
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Frequently asked questions
Is my Base64 string uploaded to a server?+
No. Decoding runs entirely in your browser. Since Base64 often wraps sensitive data like auth headers and JWT payloads, OkConverter deliberately never transmits it — nothing leaves your device.
Why does it say my input is not valid Base64?+
Valid Base64 uses only A–Z, a–z, 0–9, “+”, “/” and up to two trailing “=” padding characters. Truncated strings or stray characters (a common copy-paste issue) trigger the error. URL-safe Base64 (with “-” and “_”) should have those swapped back to “+” and “/” first.
Can it decode Base64 that contains binary data?+
This tool is built for text: output is interpreted as UTF-8. Decoded binary (images, ZIPs) will appear as garbled characters — though the downloaded .txt still contains the raw decoded bytes.
Does it handle Base64 with line breaks?+
Yes. All whitespace — spaces, tabs, and the 76-character line wrapping used by MIME email — is stripped before decoding.