Files that run into a 2 MB limit
2 MB is roomy for a form or a few scans, and tight for a document that runs to dozens of pages or is full of pictures. The files it tends to catch are:
- Theses, dissertations and research reports with photographs, maps, microscope images or screenshots
- Portfolios for design, architecture or photography applications, where most pages are large images
- Long scans, such as property papers, case files, medical records or a stack of certificates scanned in one go
- Application bundles: a completed form followed by every supporting document the organisation asked for
- Email attachments you want small enough to send quickly and open easily on a phone
The limit is set by whoever receives the file, so read their instructions, including whether 2 MB applies to each file or to everything you upload together.
This page aims for 2,000 KB, or 2,000,000 bytes. Other systems count 2 MB as 2,048,000 or 2,097,152 bytes, so a file that meets this target is under 2 MB on all of them. The result card counts in units of 1,024, so a file right at the target shows as about 1.91 MB.
Reports, theses and portfolios: keeping text and links
In a document made on a computer, the words, fonts, tables and vector charts take up very little space. The megabytes are nearly always in the pictures: photos inserted at full camera resolution, screenshots, scanned appendices. So the compressor starts there, with two passes over the images alone:
- First pass: each image is re-encoded as a JPEG at 65% quality, with its longest side capped at 1,600 pixels.
- Second pass, only if the first isn't enough: 45% quality and a 1,100 pixel cap.
Nothing else in the file changes. Text stays selectable and searchable, links in your references still open, bookmarks and internal links still jump to the right page, and form fields still work. If either pass gets the file under 2 MB, the result card says text kept selectable.
When the image passes can't help
Some images are skipped because a browser can't re-encode them safely: CMYK images, which often turn up in PDFs prepared for a print shop, JPEG 2000, the black-and-white formats some office scanners use, very small images and any image that wouldn't come out clearly smaller. If those carry most of the weight, the compressor moves on to rebuilding the pages as images, and that copy loses its links and selectable text.
For a portfolio or thesis, it's usually better to fix the source. Export a fresh PDF from the original program with smaller pictures, or in Word for Windows choose Save As, pick PDF and select Minimum size (publishing online). Then compress the new file here.
Long scans: how many pages fit in 2 MB
Scanned pages are pictures, so a scan of 30 or 40 pages can run to tens of megabytes. Scans stored as ordinary colour or greyscale JPEG images go through the same image passes first. On a full A4 page, 1,600 pixels works out at roughly 137 DPI and 1,100 pixels at roughly 94 DPI. For a scan, text kept selectable on the result card simply means those passes were enough: a scan has no selectable text to begin with.
If the passes aren't enough, every page is rebuilt as a JPEG picture at one DPI shared by the whole document, starting at 150 and stepping down until the file fits. This rough guide is for dense A4 pages of print. Pages with more white space come out sharper, and pages of colour photographs softer.
| Scanned pages | Space per page | Rebuilt at about | How it reads |
|---|---|---|---|
| Up to 4 | 500 KB or more | 150 DPI | The sharpest setting the tool uses, usually with room to spare |
| 5–8 | 250–400 KB | 120–150 DPI | Crisp, including stamps and small print |
| 10–12 | 165–200 KB | Around 100 DPI | Clear for normal print |
| 16–20 | 100–125 KB | Around 85 DPI | Readable at normal zoom; footnotes soften |
| 25–30 | 65–80 KB | 60–72 DPI | Fine on screen, but zoom into figures and dates |
| 40–60 | 33–50 KB | 50–60 DPI | A last resort: small print may not survive |
| More than 60 | Under 33 KB | May not fit | Split the file or send only the pages needed |
The table only matters when the result card shows a DPI. When it does, use it to decide whether to accept the result or split the scan first.
Putting an application bundle into one 2 MB file
When a form wants everything in a single PDF, the order you do things in makes a difference:
- Remove what isn't needed. Blank backs of single-sided pages, duplicate copies and cover sheets all take up space. Take them out with Delete PDF Pages.
- Merge, then compress. Join the documents with Merge PDF, dragging them into the order the instructions list, and compress the merged file here. Compressing each part to 2 MB first doesn't work, because merging adds their sizes together.
- Check the finished file. Scroll through every page of the compressed copy, so a soft or missing page is caught before you submit.
If the form accepts several uploads, the reverse can work better: cut a long scan into parts with Split PDF, and each part gets its own 2 MB. If some pages began as phone photos, turn the photos into pages with JPG to PDF on the Small file setting rather than merging full-size camera pictures. For stricter limits there's compress PDF to 1 MB.
Long files take a little patience
Because nothing is uploaded, your phone or computer does all the work. A long scan may be rebuilt more than once at different DPI settings before the tool settles on the sharpest one that fits, and older phones take noticeably longer than laptops. Keep the tab open until the progress bar finishes. Files over about 150 MB show a warning that compression may take a while.
The benefit is privacy. A thesis before submission, a signed contract or a folder of medical records stays on your device the whole time, with no account, no watermark and no limit on how many files you compress.