We have all been there. You attach a PDF to an email and get the dreaded message: "File too large." Or a photo from your phone is 12 MB and the form you are filling in only accepts 2 MB.

Here is a simple, free way to fix both problems in under a minute, without installing software and without creating an account.

The problem with most "free" online tools

Many online file tools ask you to upload your document to their server. That is fine for a menu or a flyer, but not for a passport scan, a contract, a payslip or a medical report. Once a file leaves your device you cannot be sure who sees it or how long it is stored.

Tools that work inside your own browser avoid this completely. The file never leaves your device. That is the approach I will use below.

Step 1: Make a PDF smaller

  1. Open the Compress PDF tool.
  2. Drag your PDF onto the page.
  3. Pick a quality level. "Medium" is usually the best balance: text stays sharp and size often drops by half or more.
  4. Download the result.

Tip: if the file is still too big, the culprit is usually large photos inside the PDF. Try a stronger compression level, or split the document into two parts with the Split PDF tool.

Step 2: Shrink a photo to a specific size

  1. Open the Compress Image tool.
  2. Drop in your JPG or PNG.
  3. Lower the quality slider until the size meets the limit of the form or email.

If a website demands exact dimensions (for example 800 x 600), use the Resize Image tool first, then compress.

Step 3: Fix the format problem

Phones now save photos as HEIC, which many websites reject. Convert them with the HEIC to JPG tool. Need to turn several photos into one document? JPG to PDF combines them in the order you choose.

A quick checklist before you send

  • Compress first, then check the file opens properly.
  • Keep the original in a safe folder in case you need the full quality later.
  • For sensitive documents, prefer tools that process files on your device.

Where I do this

I use ConvertProKit, a free collection of over 100 tools for PDFs, images, video and audio. It needs no sign-up, and the file tools run on your device, so nothing is uploaded. It also has a Flow feature to chain several steps (for example resize, then compress, then convert) over a whole batch of files at once.

If you have a favourite trick for keeping files small, share it in the comments.