How to reduce the size of a PDF so you can email it or upload it to a portal

You try to attach a PDF to an email and get a warning that the file is too big. Or you fill out an online application and, when you upload your document, the portal says the maximum allowed is 2 MB. It's one of the most common situations when working with PDFs, and it almost always has a quick fix.

Why some PDFs are so big

A text-only PDF exported from Word or a billing system usually weighs less than 1 MB even with several pages. What makes the size shoot up is images:

• Scanned documents. Each page is a photograph. A scanner set to high resolution can produce 2 or 3 MB per page.
• Photos taken with a phone and converted to PDF. Today's cameras take images of 12 megapixels or more, far more than you need to read a document.
• Presentations and catalogs with large photos or full-page backgrounds.

That's why compressing a PDF mainly means reducing the resolution and optimizing those images while keeping the text sharp.

How big should your PDF be?

It depends on where you're sending it. These are common guidelines:

• Email: Gmail allows attachments of up to 25 MB and other services are around 20 MB. Even so, it's best to stay under 10 MB: the recipient may have a lower limit, and lighter files open faster on a phone.
• Application portals, job boards and schools: many limit each file to 1, 2 or 5 MB. The limit usually appears next to the upload button; check it before compressing.
• WhatsApp: accepts very large documents, but a light PDF downloads faster and doesn't eat up the recipient's data.

How to compress a PDF step by step

1. Open the Compress PDF tool on SoloHazlo and select your file.
2. Wait for the process to finish. Scanned documents may take a few more seconds, because each page is optimized.
3. Download the compressed file and compare its size with the original (on Windows, right-click → Properties; on a phone, it shows in the downloads list).
4. Open it and check that it reads well, especially small numbers, signatures and stamps. If you're going to print it, zoom to 100% to check it.

If the PDF is still too big

When a file has already been compressed, compressing it again barely reduces its size and can make the quality worse. In that case, try these alternatives:

• Remove the pages you don't need. A 12-page bank statement can be cut down to a single page if you're only asked for your address. Use Extract pages or read the guide how to take just one page out of a PDF.
• Split the document. Some portals let you upload several files. With Split PDF you can split it into smaller parts.
• Scan again with different settings. For text documents, 150 or 200 dpi (dots per inch) in grayscale is enough. Scanning in color at 600 dpi produces huge files without making them any easier to read.

Common mistakes

• Taking photos in poor light or at an angle. Besides being bigger, they look bad when compressed. Take the photo straight on, in good light and without shadows.
• Compressing after adding a password. Compress first and, at the end, if you need to, use Protect PDF.
• Renaming the file to “.pdf” without actually converting it. A renamed image is still an image, and the portal will reject it.

Frequently asked questions