File size limits

The Base64 file and data URI tools accept files up to 10 MB. The checksum tool has no fixed limit because it streams.

Why 10 MB

Base64 inflates data by about a third, and the encoded result is held in memory as a string, rendered into the page, and copied to the clipboard. A 10 MB file becomes roughly 13 MB of text, which is already more than any of those operations handle comfortably.

Checksums are different

The file checksum tool reads the file in chunks and never holds the whole thing in memory, so large files work. A progress bar appears while it runs.

Above the limit

• For checksums, use the checksum tool rather than encoding the file.
• At the command line, base64 on macOS and Linux, or certutil on Windows.
• If the goal was inlining an asset, a file that size should not be inlined at all — the data URI page explains why.