How to Increase File Size on Windows Without Software

Windows can increase a file’s size without extra software: resize and re-save an image in Paint, re-print a document through Microsoft Print to PDF, or create padding with the fsutil command. None of the three lets you specify an exact target size, which is their main limitation.

Method 1: Paint (images)

Open the image in Paint, choose Resize, switch to Pixels, untick "Maintain aspect ratio" if you need exact dimensions, and enter larger values. Save As → JPEG or PNG. More pixels means more bytes, and saving a JPG as a PNG usually multiplies the size several times over because PNG does not use lossy compression.

The catch: Paint gives you no size preview and no quality control, so hitting a specific target means resizing, saving, checking the file in Explorer, and repeating.

Method 2: Microsoft Print to PDF (documents)

Open the document, press Ctrl+P and choose "Microsoft Print to PDF". Printing an existing PDF back through this driver re-rasterises it, which typically produces a larger file than the original. Printing at a larger paper size increases it further.

The catch: the output is a fresh rasterisation, so text in the result is no longer selectable or searchable. That can fail a portal that checks for extractable text.

Method 3: fsutil (any file — with a serious caveat)

Open Command Prompt as administrator and run fsutil file createnew padding.txt 102400 to create a file of exactly 102,400 bytes. This is genuinely exact, which is why it gets recommended.

The catch is important: fsutil creates a new empty file, it does not extend an existing one. Appending its output to a JPG or PDF with copy /b produces a file that many strict validators reject, because the trailing bytes sit outside the structure the format defines. It is not a safe way to pad a document you are about to submit.

The shorter route

If the requirement is an exact figure, the browser tool on this site writes the padding into the marker segments and chunks the format specification reserves for exactly this kind of data, so the result is both exactly the size you asked for and structurally valid. It runs locally in Edge or Chrome, with nothing installed and nothing uploaded.