What's the difference between a data URI and a plain Base64 string?

A data URI includes a prefix like data:image/png;base64, that specifies the MIME type before the actual encoded data begins. A plain Base64 string is just the encoded data with no such prefix, which is why you need to specify the MIME type and filename yourself for a plain string.

Is there a file size limit?

No practical limit imposed by this tool — decoding happens entirely in your browser's memory, so the real limit is how much memory your device and browser tab have available, not a server upload cap.

Why did the download open as the wrong file type?

Check that the MIME type you entered actually matches the original file's format. If the Base64 data came from a data URI, the MIME type is already included and detected automatically, so this typically only happens with a manually-specified MIME type for a plain Base64 string.

Can this convert a file back to Base64 too?

That's the reverse operation — use the Base64 Encoder / Decoder tool to go from a file to Base64 text; this tool specifically goes the other direction, from Base64 text back to a file.

Base64 to Blob Converter

Convert a Base64 data URI into a downloadable file, without server-side size limits.

TL;DR: Base64 to Blob Converter is a free, browser-based tool that lets you convert a Base64 data URI into a downloadable file, without server-side size limits.

Base64 string or data URI

MIME type (only needed for a plain Base64 string, not a data URI)

Filename

About this tool

Convert a Base64-encoded string — either a plain Base64 string or a full data URI like data:image/png;base64,... — into a real downloadable file. This is the reverse of Base64 encoding: instead of turning a file into text, it decodes that text back into actual binary data (technically a Blob, the browser's binary-data object) that you can save. Useful whenever you have Base64 data from an API response, a database export, or an embedded data URI, and need the actual file back.

Key Features

Accepts either a full data URI or a plain Base64 string
Auto-detects the MIME type and filename extension from a data URI
Lets you set a MIME type and filename manually for plain Base64 input
No file size limit imposed by a server, since decoding happens locally
Runs entirely in your browser — nothing is ever uploaded

How to Use

Paste your Base64 string or data URI.
If it's a plain Base64 string (not a data URI), set the MIME type and filename.
Click Convert to decode it and download the resulting file.

When to use it

Recovering a real file from a Base64 string returned by an API response
Extracting an embedded image from a data URI found in HTML or CSS source
Converting a database export field stored as Base64 back into its original file
Testing how a specific Base64 payload decodes without writing any code
Quickly checking whether a piece of Base64 text is valid before using it elsewhere

Tips & limitations

A data URI already tells this tool the MIME type (the part between data: and ;base64,) — the MIME type and filename fields are only needed for a plain Base64 string with no such prefix
If the decoded output doesn't open correctly, double check the MIME type matches the actual file format — a mismatched type won't corrupt the data, but some apps refuse to open a file whose extension doesn't match its actual content
Base64 text with line breaks or unexpected whitespace can fail to decode — this tool strips whitespace automatically before decoding, but genuinely corrupted or truncated Base64 still can't be recovered
Very large Base64 strings (tens of megabytes of text) are handled the same way as small ones, since decoding happens in memory in your own browser rather than being limited by a server upload cap

Frequently Asked Questions

: A data URI includes a prefix like data:image/png;base64, that specifies the MIME type before the actual encoded data begins. A plain Base64 string is just the encoded data with no such prefix, which is why you need to specify the MIME type and filename yourself for a plain string.
: No practical limit imposed by this tool — decoding happens entirely in your browser's memory, so the real limit is how much memory your device and browser tab have available, not a server upload cap.
: Check that the MIME type you entered actually matches the original file's format. If the Base64 data came from a data URI, the MIME type is already included and detected automatically, so this typically only happens with a manually-specified MIME type for a plain Base64 string.
: That's the reverse operation — use the Base64 Encoder / Decoder tool to go from a file to Base64 text; this tool specifically goes the other direction, from Base64 text back to a file.

Cite This Tool

Referencing this tool in a paper, article, or bibliography? Copy a ready-made citation below.

NexLove.org. (2026). Base64 to Blob Converter [Software]. https://nexlove.org/tools/base64-to-blob-converter.html

“Base64 to Blob Converter.” NexLove.org, 2026, nexlove.org/tools/base64-to-blob-converter.html.

NexLove.org (2026) Base64 to Blob Converter. Available at: https://nexlove.org/tools/base64-to-blob-converter.html (Accessed: 2026).

@misc{nexlove_base64_to_blob_converter,
  title = {Base64 to Blob Converter},
  author = {{NexLove.org}},
  year = {2026},
  url = {https://nexlove.org/tools/base64-to-blob-converter.html}
}

Embed This Tool

Add the live Base64 to Blob Converter tool to your own website with this snippet — it loads the real, working tool in an iframe, not a static screenshot.

<iframe src="https://nexlove.org/embed/base64-to-blob-converter.html" width="100%" height="600" style="border:1px solid #e2e8f0;border-radius:12px" title="Base64 to Blob Converter — NexLove.org" loading="lazy"></iframe>

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