DOC is the pre-2007 Word binary, which most modern tools open reluctantly. TXT is plain text, with no markup of any kind. LibreOffice sits between the two, and this page says exactly what happens to a DOC file on the way to becoming a TXT one.
What runs when a DOC file becomes TXT
LibreOffice 24.2, on a machine we rent and watch. Your DOC file is uploaded once, LibreOffice runs once, the TXT comes back, and neither file is kept. DOC to TXT is one of the 3649 pairs that engine was probed on with a real file, which is why it has a page here and why the pairs the probe could not prove do not.
What survives from the DOC into the TXT
The text, and nothing standing between a program and it.
A TXT that anything can open. No version, no schema, no library: this is the format you reach for when the thing on the other side is a script rather than a person.
What DOC to TXT costs you
Everything that is not the content itself: styling, headings, images, and any structure the DOC file used to describe itself. A TXT is one flat thing, on purpose.
Where DOC and TXT files come from
DOC. Word wrote it before 2007. It is an OLE2 compound binary rather than a zip of XML, and that difference is why modern parsers, mail filters and document pipelines increasingly refuse it outright instead of half-reading it.
If a model is going to read the TXT
Structure is what survives from the DOC file, and structure is what a model needs. DOC in, TXT out, with the heading tree intact instead of flattened into one long paragraph.
DOC to TXT, measured rather than promised
Running DOC to TXT against the real engine with a real file, LibreOffice wrote 268 bytes of TXT in 1.1 seconds, machine otherwise idle. That is one DOC file on one day and not an average, which is why the number is given together with the file that produced it.
The DOC to TXT verdict was reached by reading the internal type and finding a witness word, meaning the output was read back and recognised. Which check was used matters, because they do not all prove the same thing, and a status code of 200 proves nothing whatsoever about whether the TXT file has anything inside it.
The same DOC file, sent somewhere else
Other outputs the probe measured out of a DOC file, so the cost of choosing TXT can be read against something. Sizes do not compare across engines, because each family was probed with its own DOC witness file.
DOC to PDF: 11,917 bytes in 1.1 seconds, verified by a format signature.
DOC to DOCX: 5,462 bytes in 1.1 seconds, verified by a format signature.
DOC to HTML: 1,626 bytes in 1.1 seconds, verified by reading the internal type and finding a witness word.
DOC to RTF: 4,321 bytes in 1.1 seconds, verified by reading the internal type and finding a witness word.
DOC to ODT: 12,484 bytes in 1.2 seconds, verified by reading the internal type and finding a witness word.
Other ways into TXT, and what they measured
Among the published routes into TXT, DOC is the second largest output of the 11 measured. The witness files differ, so this ranks the probe run and not your document.
AZW3 to TXT: 219 bytes in 0.6 seconds.
CSV to TXT: 114 bytes in under a tenth of a second.
HTML to TXT: 270 bytes in under a tenth of a second.
JSON to TXT: 264 bytes in under a tenth of a second.
MD to TXT: 264 bytes in under a tenth of a second.
What we will not pretend about DOC to TXT
A DOC file over 25 MB is refused before the upload finishes rather than after it, so you do not wait for a rejection.
A DOC to TXT run that passes 90 seconds is killed, and the LibreOffice process is killed with it. A run left behind would sit on one of the machine's two cores until somebody noticed.
LibreOffice is serialised on purpose, one document at a time per worker, because each soffice instance takes 150 to 300 MB on a machine with 3.8 GB. Measured ceiling: 23 DOC conversions in flight and roughly 0.9 a second sustained. Past that the queue answers 429 rather than falling over, which was tested at 32 at once.
Two thirds of the pairs you could imagine in this family do not exist, and it is worth knowing why before you go looking for one. LibreOffice converts inside whichever application opened your file: from a spreadsheet it writes spreadsheets, flat text, HTML and PDF, and it will not write a .docx no matter how it is asked. It returns nothing at all rather than something wrong. Of 113 combinations probed on this engine, 64 came back with a real file and the rest were refused outright.
This pair is one of the 64. It was proved by sending a real DOC file through the live route and reading the TXT that came back: not its extension, its internals, plus a marker word planted in the source and found again in the output. The traits named further up this page come from a second probe that looks for each of them one by one.
One DOC file at a time, chosen in the browser. There is nothing else to set up and nothing else on offer.
DOC to TXT: what people ask
What actually converts my DOC file to TXT?
LibreOffice does it, 24.2, on a machine we rent and watch. Not a browser trick and not somebody else service: the DOC file is uploaded once, LibreOffice runs once, the TXT comes back, and neither file is kept afterwards.
How long does DOC to TXT take?
On the file the probe used, LibreOffice took 1.1 seconds and wrote 268 bytes of TXT. That is one real measurement on one real DOC file, not an average and not a promise about yours: a larger DOC takes longer, and past 90 seconds the run is stopped.
What do I lose going from DOC to TXT?
The one to know about first: Everything that is not the content itself: styling, headings, images, and any structure the DOC file used to describe itself. A TXT is one flat thing, on purpose.
Why is my TXT so much smaller than the DOC?
Because a TXT holds the content and nothing else. Styling, fonts, images, headings and the file structure around them are all gone by design. What is left is the words, in order.
Is DOC to TXT free?
There is a free allowance every month, and one DOC to TXT conversion costs half a credit against it. When the allowance runs out the tool says so and stops, rather than quietly handing you a worse TXT.