File Converter FREE
Drop a file and see what it can become. Detects the real format from its bytes, converts spreadsheets, data, text, audio and video in your browser, and hands images and PDFs to the tools built for them.
Drop a file here, or choose one
CSV, TSV, JSON, YAML, XML, Markdown, HTML, plain text, Excel workbooks, and audio and video. The format is read from the file itself, not from its name.
Your files
Convert to
Columns
Uncheck a column to leave it out, type over a name to rename it, and use the arrows to reorder. The preview below follows.
What was read
What this converter does and does not do
Reads the bytes, converts in your browser, delegates the rest
The format is identified from the file content rather than from its name, every conversion runs on this device, and nothing is uploaded - audio and video included, which is why the media engine is a download rather than a server. Where another POLPROG tool already owns a job - images, PDFs, JSON editing - this one links to it instead of shipping a second, weaker engine. Conversions that would lose something say so before you download the result.
FAQ
Are my files uploaded?
No. Every conversion here runs in your browser: the file is read with the File API, converted in memory and handed back as a download. Nothing you convert reaches a server; the only thing kept in this browser is your last choice of target format and options.
How does it know what my file is?
From its bytes. Formats with a signature - Excel workbooks, images, PDFs - are recognised by it; CSV, JSON, YAML, Markdown and plain text have none, so those are recognised by structure: a delimiter that splits every line into the same number of fields is a table, a document that parses as JSON is JSON. When the content disagrees with the extension you are told, and the content wins.
Why can I not convert a PDF to Word here?
Because doing it badly is worse than not doing it. A faithful PDF-to-DOCX conversion needs layout reconstruction that a browser cannot do, and the usual result is a document of text boxes that falls apart the moment anyone edits it. The PDF Toolkit does the PDF operations that can be done properly - merge, split, compress, rotate, protect, images in and out - and this converter links to it rather than pretending.
What happens to nested JSON when I convert it to CSV?
You choose. Nested objects and arrays can be flattened into dotted columns (user.name, user.tags.0), or the conversion can stop and name the paths that will not fit in a table. What it never does is silently drop them or stringify a whole branch into one unreadable cell, which is what most converters do.
Does converting CSV to XLSX keep my formatting?
There is no formatting in a CSV to keep. The workbook it produces holds the values, with numbers written as numbers so Excel can add them up and identifiers like leading-zero codes kept as text so they survive. It has no styles, formulas or charts, and it does not claim to.
Which YAML does it understand?
The common subset: mappings, sequences, scalars, block strings, comments and inline flow collections. Deliberately not tags, anchors or custom types - a YAML parser that can construct arbitrary objects is a code-execution surface, and this one runs on files from strangers. A document using those features is reported rather than half-read.
How does audio and video conversion work without uploading anything?
A WebAssembly build of FFmpeg runs in a worker on this page. The first media conversion downloads it - about 8 MB, once, cached afterwards - and every frame is then decoded and re-encoded on your own machine. That is also the catch: it runs on a single core, so a ten-minute video takes minutes rather than seconds. The tool estimates the wait before you start, shows FFmpeg's own progress while it runs, and lets you stop it. MP4 uses H.264 with AAC, WebM uses VP8 with Vorbis, and MP3 and WAV are offered wherever there is sound to extract. VP9 and Opus are deliberately not offered: both crash in this single-threaded build, and an option that fails is worse than one that is missing.
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