Where to see the size on each device
- Windows: right-click the file and choose “Properties”. The “Size” field shows KB or MB.
- Mac: select the file and press Cmd + I (“Get Info”), or use the Finder list view.
- iPhone: in the Files app, press and hold the file and choose “Info”.
- Android: in the Files or Google Files app, tap the file's three dots and choose “Details”.
KB, MB and why the numbers don't always match
1 MB is 1,024 KB on most systems, but some portals count 1,000. If your file is exactly at the limit, the portal may reject it. Leave a small margin.
How big a PDF usually is
- A short text document: from tens of KB to a couple of hundred.
- A black-and-white scanned page: roughly 50 to 300 KB.
- A colour page scanned or photographed with a phone: 1 to 5 MB or more.
These are rough figures: they depend on resolution and scanner. That's why a file of 10 colour-scanned sheets can pass 20 MB.
If it's bigger than the limit
- One file that's too big: compress it to the size you need. It happens in your browser, without uploading it.
- Several documents that add up to too much: compress each one separately or split the PDF by size if the procedure accepts several files.
- You're going to scan again: use greyscale for text documents; you'll see the difference. More tips in the guide to scanning with your phone.
- You don't know how much you can upload: check the limits each body publishes, with source and date.
Frequently asked questions
How do I know if my PDF fits in 1 MB?
Check its size in the file's properties: if it says under 1,024 KB, it fits. If the portal counts 1,000 KB per MB, aim for a bit below.
Why does a one-page PDF weigh several MB?
Almost always because the page is a high-resolution colour photo. Compressing it or rescanning in greyscale shrinks it a lot.
Does compressing a PDF reduce its quality?
It depends on how much it has to shrink. If lossless compression is enough, nothing changes. If it has to go lower, resolution is reduced, and the tool warns you if the text might become hard to read.
Tools
- Compress PDFShrink a PDF to the exact size you need: 100 KB, 200 KB, 1 MB…
- Resize ImageShrink your photos to 20, 50, 100 KB… and set their pixel size.
- ID PhotoCrop your photo for a Spanish DNI, passport or TIE and download it to upload or print.
- Merge PDFCombine several PDFs and photos into one PDF, in any order.
- Convert ImageTurn iPhone HEIC, WEBP or PNG photos into JPG, PNG or WEBP, several at once.
- PDF to JPGTurn every page of a PDF into a JPG or PNG image.
- Split PDFExtract pages, separate them one by one or split a PDF by maximum size.
- Organize PDFRotate, reorder and delete PDF pages without losing quality.
- Sign PDFDraw, type or upload your signature and place it on your PDF, with date and initials.