How to Decode Base64 Back to Text

A Base64 string in an API response, a config value, a data URL — decoding it back to readable text is usually a one-click operation, except when the source contains non-English text, or the string itself is malformed. Here's what a decoder actually needs to handle correctly.

Two Ways This Commonly Goes Wrong

Invalid input. Not every string that looks like Base64 actually is — wrong characters, broken padding, or a string that's just plain text mistaken for encoded data. The browser's native atob() throws on genuinely invalid input, which QR Ivify's Base64 Decoder catches and reports as a clear "Invalid Base64 string," rather than letting the error crash the page or produce silently wrong output.

Unicode corruption. The reverse of the encoding problem: decoding Base64 back to a raw string with atob() alone works fine for plain ASCII, but Vietnamese, CJK, or emoji text needs the decoded bytes interpreted as UTF-8 (via TextDecoder) to come back correctly — skip that step and non-English text decodes into garbled, unreadable characters even though the Base64 itself was perfectly valid.

Step by Step

1. Open the Base64 Decoder.
2. Paste a Base64 string into the box.
3. Click "Decode."
4. Copy or download the decoded text.

What "Invalid Base64" Actually Means

Base64 uses a specific, small character set (A–Z, a–z, 0–9, +, /, with = for padding). A string containing anything outside that set — or with padding in the wrong place — isn't valid Base64, and there's no reasonable way to guess what was meant. Rather than attempting a "best effort" decode that could produce misleading output, an invalid string gets a direct error instead.

Frequently Asked Questions

What happens if I paste invalid Base64? You'll see "Invalid Base64 string" rather than garbled or silently wrong output.

Does this handle Vietnamese, emoji, and other Unicode text correctly? Yes — decoding goes through proper UTF-8 byte conversion, so Unicode text decodes back exactly as it was encoded.

Does this upload my text anywhere? No. Decoding happens entirely in your browser.

Is Base64 encryption? Is my decoded text safe from others? No — Base64 isn't encryption, and anyone with the encoded string can decode it just as easily. It provides no confidentiality.

Try It

Need to decode a Base64 string back to readable text? QR Ivify's free Base64 Decoder handles Unicode correctly and reports invalid input clearly. Need to encode text instead? Try Base64 Encoder. Decoding a token? See JWT Decoder.