It is 11:40 at night, the deadline is 11:59, and the learning platform says your file is too large. Or worse: one classmate sent her chapter in Word, yours is in Google Docs, another one built the appendices in Excel, and the guidelines say "a single PDF file with numbered pages". If you are at university, this scene will play out at least once a semester.
This guide pulls together what you need so the PDF is never the problem: how to export properly from Word, Google Docs or LaTeX, how to combine parts written by different people, how to number and compress without wrecking the work, and what to check before you hit "Submit". At the end there is a list of the mistakes that come up most often the night before a deadline.
Exporting to PDF without losing formatting or fonts
The first mistake is hitting "save as" with whatever option appears and hoping for the best. A properly exported PDF keeps the fonts embedded, respects page breaks and keeps the text selectable, which is what plagiarism checkers and a supervisor who wants to leave comments both need.
In Word: File, Save As (or Export), choose PDF. Under "Options" make sure fonts are embedded and, if your thesis has a linked table of contents, that bookmarks are created from headings. Avoid "printing" to PDF through a virtual printer: it usually drops the links in your table of contents and sometimes turns unusual fonts into images.
In Google Docs: File, Download, PDF Document. Google Docs embeds its own fonts without trouble; if you used a font carried over from an original Word file, check the result, because it may have been silently replaced by Arial.
In LaTeX: pdflatex, xelatex and lualatex already produce PDFs with embedded fonts. If your university requires PDF/A for its repository, check your department's template, which usually includes the right package.
Merging chapters and appendices from different group members
In group projects everyone writes their part in their own tool and at the end somebody has to assemble the document. Copying and pasting everything into one Word file is a recipe for broken styles, drifting tables and scrambled references. The clean approach is for each person to export their part to PDF with the same page size (A4 or Letter, whatever your department requires) and then merge the PDFs in order.
- 1. Ask every member for their part already as a PDF, named with a number and the content: 01_cover.pdf, 02_contents.pdf, 03_ch1_literature_review.pdf, 09_appendices.pdf.
- 2. Open /merge on fastpdfnow and drag all the files in. They are processed in your browser, so you are not uploading your thesis to any server.
- 3. Drag them into the correct sequence. Numbered file names make this almost automatic.
- 4. Download the merged file and read it from start to finish, paying special attention to the seams between chapters: someone may have left a blank page at the end.
- 5. If some appendices are Excel sheets or photos (scanned surveys, fieldwork pictures), convert them first: Excel exports to PDF just like Word, and photos can be turned into a PDF at /images-to-pdf.
Adding page numbers when the guidelines require them
Many thesis guidelines require continuous page numbering, and when you merge PDFs from different sources it is common for each part to carry its own numbering starting at 1, or for none of them to have any. It is also common that the cover page should stay unnumbered while everything after it is numbered.
If you are still in Word and it is a single document, use Word's own page numbering. If you already have the merged PDF, it is faster to number it at /page-numbers: choose the position (bottom centre or bottom right, depending on your department), which page to start counting from, and which number to start with. That lets you leave the cover blank and start at 1 or 2 on the next page. Check that the new numbering does not overlap old numbering one of the chapters brought along; if it does, ask for that part without page numbers and merge again.
Compressing for the learning platform or plagiarism checker
University platforms usually cap the size of each file. There is no universal number: check the exact limit on the platform or in your course guidelines. What is universal is that a thesis with twenty screenshots, phone photos and charts pasted from Excel can easily weigh far more than allowed, and the culprit is almost always images, not text.
If you already have the PDF and need it under a specific size, use /compress and enter the target size the platform demands. The tool lowers image resolution until it reaches that size. Check the result: tables and charts must still be readable. If the platform demands something extremely small and your thesis has many figures, ask your lecturer whether appendices can be submitted as a separate file.
Extracting just the chapter your supervisor wants to see
Your supervisor writes: "send me only the revised chapter 3". Sending all 180 pages makes it less likely they review it on time. Open /split, load your full thesis and enter the page range for the chapter, for example 45-72. You download a small PDF with just those pages. Name it clearly: Thesis_Ch3_v2_for_review.pdf. Your supervisor sends it back with comments, you fix the original document and export everything again.
Landscape tables that ended up sideways
A consistency matrix, a Gantt chart or a wide results table usually belongs on a landscape page. When that appendix is exported by someone else or comes from Excel, it is common for those pages to show up rotated 90 degrees in the merged PDF.
If it is only a handful of pages, there is no need to redo the export: open /rotate, load the PDF, select only the affected pages and turn them the right way. If it is many pages or it happens with every new version, fix the source instead: in Word, that appendix should sit in its own section with landscape orientation, not as a table rotated like an image.
Naming by version and checking before you submit
A file called "thesis final FINAL really final.pdf" is a genuine source of errors: you end up submitting the wrong version. Adopt a fixed pattern from the first draft: Thesis_Surname_v3_2026-10-20.pdf. A date in year-month-day format makes files sort themselves in any folder, and the version number tells you at a glance which one is the latest.
When you think it is ready, run this five-minute check:
- Open it on a different device (your phone, a classmate's laptop). If it looks fine on your computer only because you have the fonts installed, another machine will reveal immediately whether they were embedded.
- Search for a word with Ctrl+F to confirm the text is selectable.
- Flick through every page in thumbnail view to spot blank, rotated or duplicated pages at the seams between chapters.
- Confirm the file is under the platform's size limit and that the name follows whatever format you were asked for.
Common mistakes the night before the deadline
These are the ones that come up again and again. If you recognise one, you know what to check first.
- Exporting from a computer that does not have the template's font: the PDF comes out in a different typeface, the page breaks shift and the table of contents no longer matches.
- Merging chapters in the wrong order because the files were called "Luis part.pdf" and "my part.pdf". Put numbers at the start of the file names.
- Compressing to the maximum "just in case" and submitting unreadable figures.
- Assuming the platform "will take it anyway" and discovering at 11:58 that it rejects the file for being too large. Test an upload early, even with a draft.
- Submitting a scan of the printed document, with the text as an image. If you had the original file, export from there.
Key points
- Export from Word, Google Docs or LaTeX using the proper PDF option (not a virtual printer) to keep fonts, links and selectable text.
- For group work, have everyone deliver their part as a numbered PDF and merge them in order at /merge.
- Add numbers at /page-numbers after merging if the guidelines require it, and compress at /compress only down to the platform's real limit.
- For your supervisor, extract just the chapter with /split; for sideways tables, use /rotate on the affected pages only.
- Name files by version and date, and open the PDF on another device before submitting.
Common questions
Why does my PDF look different on my supervisor's computer?
Almost always because the fonts were not embedded on export. It looks right on your machine because you have them installed; on another, the reader substitutes them. Export again from Word with font embedding enabled or from Google Docs, and check on a second device.
Can the plagiarism checker read a PDF I merged on fastpdfnow?
Yes, as long as the original parts have selectable text. Merging does not change the content of the pages; it only puts them in sequence. What a checker cannot read is pages scanned as images, wherever they come from.
Is it safe to process my thesis in an online tool?
On fastpdfnow the file is processed inside your browser and never uploaded to a server, so your unpublished research never leaves your device. With other tools, read their policy before uploading work you have not published yet.
How big should my thesis PDF be?
There is no universal figure. Each platform sets its own limit; check it on the platform or in the course guidelines. As a rule of thumb, a text-heavy thesis with few images is small; photos and screenshots are what add weight.
Written by the fastpdfnow team in Lima. We build the tools and write the guides from the questions people send us.