File to Base64 Converter
How it works
Choosing a file reads it with FileReader.readAsDataURL, the same local,
in-memory read every upload on this site uses — nothing about the file, not even its name,
leaves this tab. The result is a data:<mime-type>;base64,<data>
string: the MIME type your browser detected from the file, followed by the file's own bytes
re-encoded as Base64 text.
Frequently asked questions
Does my file get uploaded anywhere?
No. The file is read with the browser's FileReader API, which is a local, in-memory read — the exact same guarantee every other upload-enabled tool on this site relies on. Nothing is sent to a server; the whole conversion happens in this tab.
What is a data URI actually for?
It lets a small file — an icon, a font, a tiny image — be embedded directly inside HTML, CSS or JSON as text, instead of being a separate file the browser has to fetch with its own network request. That is handy for a handful of small assets; it is a poor fit for anything large, since base64 text is roughly a third bigger than the original bytes.
Why is there a file size limit?
It keeps the tab from choking on something huge. Reading a file this way holds its entire contents in memory as a base64 string, and a multi-hundred-megabyte video or archive would make the page unresponsive for no benefit — this tool is meant for the small assets a data URI actually suits.