Base64 Decode
Decode any Base64 string back to text or a downloadable file — instantly, privately, in your browser.
Private by design
Base64 strings are decoded locally. Nothing is uploaded — safe for tokens and secrets.
Instant decode
Decoded output appears as you type, with charset selection for UTF-8, ASCII, and more.
Text or file output
Decode a string to text, or paste a Base64 blob and download the original binary file.
What is Base64 decoding?
Base64 decoding takes a string built from the 64 characters A–Z, a–z, 0–9, +, and / (with = padding) and reconstructs the original binary data. Every group of four Base64 characters maps back to three bytes. Decoding is how you read the contents of an encoded image, certificate, JWT payload, email attachment, or API response.
To encode in the other direction, use the Base64 Encode tool.
Frequently asked questions
›How do I decode a Base64 string online?
Paste your Base64 encoded string into the input above. The decoded text is shown instantly. To decode into a file (image, PDF, certificate, archive), switch to the File tab and paste the Base64 — you'll get a download link for the resulting binary.
›What is Base64 decoding?
Base64 decoding converts a Base64-encoded ASCII string back into the original bytes. Base64 is used to safely carry binary data through text-only channels (email, JSON, HTTP headers, data: URLs), and decoding is how you recover the original payload.
›Is this Base64 decoder safe for sensitive data?
Yes. Decoding runs 100% in your browser using the built-in atob and TextDecoder APIs. Your Base64 input is never uploaded, logged, or stored on a server — you can safely decode tokens, secrets, and private payloads.
›Why does my Base64 string fail to decode?
Common reasons: the string contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /, =); the length is not a multiple of 4 after padding; you actually have URL-safe Base64 (uses - and _ instead of + and /); or there's surrounding text like 'data:image/png;base64,' that needs to be removed first.
›Does this support UTF-8, emoji, and non-Latin scripts?
Yes. The decoded bytes are interpreted using the character set you select (UTF-8 by default). Multilingual text, accented characters, and emoji decode correctly as long as the original was encoded as UTF-8.
›How do I decode a base64 data URL?
A data URL looks like data:image/png;base64,iVBORw0KGgo… — remove everything up to and including the comma, then paste the remaining string. Switch to the File tab if you want to download the decoded image or PDF.
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