How to Compress a PDF to Any Size — Free Guide (2026)
Whether you're hitting a 1MB limit on a government portal, a 2MB cap on a job application, a 25MB email attachment ceiling, or just trying to save storage space — this guide covers everything you need to compress a PDF to any target size, for free, without uploading your file to any server.
Common File Size Limits by Platform
The right compression level depends on where you're sending the file. These limits are per-file unless otherwise noted — a multi-document submission may have the same limit applied to each file individually.
File Size Limits by Platform
Malaysian government portals (LHDN, EPF, JPA, UPU, SPA, PTPTN): 1–2MB per document
Understanding why your PDF is large tells you whether compression will work well — and how much reduction to expect. There are four main causes:
High-resolution embedded images: A scan at 300 DPI colour is the single most common cause of oversized PDFs. Each full A4 page scanned at 300 DPI colour occupies 1–3MB of raw data. A 5-page payslip history or 6-month bank statement can easily reach 8–15MB this way. Compression works by resampling these images to a lower resolution — typically 96–150 DPI for screen viewing, which looks identical in practice but stores far less data.
Uncompressed image data: Many PDF generators (including scanner apps and Word's "Print to PDF") embed images without applying any compression algorithm. The pixels are stored as-is. A compression tool's first pass often yields dramatic results simply by applying standard compression to already-embedded images.
Colour vs grayscale: Colour images carry three data values per pixel (red, green, blue) versus one for grayscale. For documents that don't visually require colour — contracts, payslips, transcripts, official letters — colour is pure overhead that adds nothing to the document's utility.
Embedded fonts, metadata, and revision history: PDFs generated from design tools or through multiple edits in Word or Acrobat can accumulate unused font subsets (fonts embedded but never used), revision history from tracked changes, and hidden metadata. These add anywhere from a few KB to several hundred KB depending on the document's history.
Key insight: In the original PDF, text is stored as vector data — mathematical descriptions of shapes — and takes up almost no space, so text itself is essentially never why your original file is large. If your text-heavy PDF is unexpectedly large, it has embedded images or was exported without compression from another application. One side effect of ShrinkPDF's compression worth knowing: it re-renders every page (including text-only pages) as an image, so the size drop applies across the board, but the compressed file no longer has a real, selectable text layer — see "Will Compression Affect Quality?" below.
Choosing the Right Compression Level
ShrinkPDF offers three compression levels, each suited to different situations:
Compression Level Guide
Light (20–35% reduction): Applies minimal image resampling — preserves near-original image quality. Best for portfolios, product photos, design work, or medical imaging where visual detail matters. Use when you need to trim a few MB without any perceptible quality change.
Balanced (40–60% reduction): The right choice for most everyday documents. Email attachments, reports, presentations, and general documents all compress well at this level. Image quality is virtually indistinguishable at normal viewing sizes on screen.
Maximum (65–85% reduction): Use when you have a hard size limit — government portals, university submissions, EPF. The smallest output; some softening is visible if you zoom in, including on text. Always verify readability after downloading.
Rule of thumb: Balanced for email, Maximum for portal uploads with strict limits. If Balanced doesn't get you under the target size, switch to Maximum.
Step-by-Step: Compress to Your Target Size
1
Check Your Current File Size
Windows: right-click → Properties → "Size on disk". Mac: right-click → Get Info. Mobile: long-press the file in Files app or Google Files. Record the original size — you'll want to confirm the compression result meets your target before submitting.
2
Open ShrinkPDF
Go to ShrinkPDF.fyi — no account, no app, no size limit. Works on Chrome, Safari, Firefox, and Edge on desktop and mobile. Everything runs locally in your browser.
3
Upload Your PDF
Click "Choose PDF File" or drag and drop. Your file stays on your device — nothing is uploaded to any server. This matters for sensitive documents like payslips, bank statements, and identity documents.
4
Choose the Right Level
Use the guidance above. For portal uploads with a 1–2MB limit, select Maximum. For email attachments where quality matters more, select Balanced. You can re-compress at a different level if the first result doesn't meet your target — just upload the original again (not the already-compressed version).
5
Download and Verify
Download the compressed file and check: (1) the file size meets your target, and (2) open the PDF and verify that text is legible and key details are clear. For documents with fine print, signatures, or IC numbers, zoom in to confirm they're readable before submitting.
Will Compression Affect Quality?
Visually, the file looks close to the original at Light and Balanced, with some softening visible at Maximum if you zoom in. But there's a more important change worth knowing about first:
What actually happens during compression
ShrinkPDF compresses a PDF by re-rendering each page as an image and re-encoding it, then assembling those images into a new PDF. This applies to every page, including pages that are purely text — there's no separate "leave the text alone" step. That's part of why it shrinks text-heavy documents effectively too. The trade-off: the compressed file is a sequence of page images, not a text document, so it loses anything that depends on real text or document structure.
Visually, it looks the same. At normal screen zoom, Light and Balanced are very close to the original. Maximum shows some softening if you zoom in, most noticeably on text.
It's no longer selectable or searchable text. You won't be able to highlight, copy, or Ctrl+F search text in the compressed file, even if you could in the original.
Hyperlinks, bookmarks, fillable fields, and digital signatures don't carry over. Since the page becomes a flattened image, anything that relied on the PDF's underlying structure is gone. If you need any of these to still work, compress a copy and keep the original for that purpose, or compress before adding a signature rather than after.
Layout and colours look unchanged. Page layout, colours, and the visual arrangement of content are preserved visually — they just exist as part of an image now, not as editable elements.
The practical test
For most uses — a payslip someone will read on screen, an ID scan someone will glance at, a form a portal will display — none of this matters and Balanced or Maximum is fine. It matters if you need to search the document later, click a link in it, or rely on a digital signature staying valid. Check which situation you're in before choosing a level.
Still Too Large After Compression?
If Maximum compression still leaves you above the target size, work through these options in order:
Re-scan at lower DPI and grayscale: If the source document is a scan, the single most effective fix is to re-scan at 150 DPI in grayscale (black and white). A single A4 page scanned this way is typically 50–200KB — well under any portal limit without any compression needed. This is more effective than any compression tool when you have access to the original physical document.
Split into smaller parts: Use the ShrinkPDF Split tool to extract specific pages or page ranges into separate files. If the portal allows multiple uploads for the same category, compress and upload each part individually.
Remove unnecessary pages: Use the Reorder tool to delete blank pages, duplicate scans, or appendix pages not required for the submission. Even removing one high-resolution page can significantly reduce the total.
Compress a second time: In some cases, running Maximum compression again on an already-compressed file yields an additional 10–20% reduction, particularly for mixed-content documents.
Use an alternative submission method: For email, share a Google Drive or OneDrive link instead of attaching. For portals, contact the helpdesk — most Malaysian government portals have an email alternative for genuinely large documents.
Compressing for Email vs Portal Uploads
Email and portal uploads have different requirements, and the right compression strategy differs:
For email (Gmail, Outlook, Yahoo): The 20–25MB attachment limit is generous for most documents. Use Balanced compression — it preserves more visual quality while still reducing file size meaningfully. Reserve Maximum for documents with hard size targets. If a file is genuinely too large for email after Maximum compression (e.g. a 200-page report), switch to sharing a link via Google Drive or OneDrive rather than compressing further.
For government portals: Use Maximum compression without hesitation. The 1–2MB limits are strict and the quality tradeoff is not meaningful for text-heavy government documents. Reviewers are reading on screen, not printing at high resolution.
For corporate email: Server limits vary. If a compressed PDF bounces with a size error, check whether the limit is per-attachment or per-email-total. A 5MB limit per email with three attachments means each file should be under ~1.5MB after accounting for email overhead.
How Different PDF Types Respond to Compression
Not all PDFs compress equally. Here's what to expect by document type:
Expected Compression Results by Document Type
Scanned documents (colour, 300 DPI): 70–85% reduction — best results of any document type
Documents with embedded photos: 50–75% reduction depending on original photo resolution
Office documents exported to PDF (Word, PowerPoint): 20–50% reduction
Text-only PDFs (contracts, letters): 40–70% reduction — every page is re-rendered as an image, so even text-only documents shrink substantially, not just image-heavy ones
Already-compressed PDFs: 5–15% — diminishing returns, little headroom remaining
If your scanned PDF shows less than 30% reduction after Maximum compression, the file may already have been compressed at the scanner level, or it may contain embedded images that are already at low resolution.
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Visually, no, at Light or Balanced — the document looks close to the original at normal zoom. Maximum shows some softening if you zoom in. What's worth knowing: the compressed file is no longer real, selectable text, and any hyperlinks or digital signature won't carry over, since ShrinkPDF re-renders each page as an image. If you only need the document to be read on screen, this doesn't matter. Always open the compressed file and verify before submitting to a portal or employer.
Will hyperlinks and digital signatures survive compression? ▼
No. Compression re-renders each page as an image, so clickable hyperlinks, fillable form fields, and any digital signature are not carried over to the compressed file. If you need those to keep working, share the original alongside the compressed copy, or compress before signing rather than after.
Is there a file size limit on ShrinkPDF? ▼
No. Unlike most free tools that cap at 10–20MB on the free tier, ShrinkPDF has no file size limit. You can compress a 200MB PDF. For very large files, processing takes longer since everything happens locally in your browser — but there is no size cutoff.
Does my file get stored on your servers? ▼
No. Your file is processed 100% locally in your browser using JavaScript. It never gets uploaded to any server at any point. You can verify this yourself: go offline after the page loads and compression will still work, because no server connection is required.
Which compression level should I use for government portals? ▼
Use Maximum compression for all Malaysian government portals (LHDN, EPF, JPA, UPU, SPA, PTPTN). These portals enforce 1–2MB limits and Maximum compression reduces most documents by 65–85%, giving you a comfortable margin. For EPF specifically, which sometimes enforces a 1MB limit, Maximum compression is essential.
What's the difference between Balanced and Maximum compression? ▼
Balanced reduces file size by 40–60% with virtually no visible quality difference at normal screen zoom — ideal for email and everyday sharing. Maximum reduces by 65–85% by compressing more aggressively — use this when you have a hard size limit to meet. Some softening becomes visible at Maximum if you zoom in, including on text, since every page is re-rendered as an image regardless of level.
My PDF is still too large after Maximum compression. What next? ▼
If the document is a scan, re-scan at 150 DPI in grayscale — this is almost always more effective than any compression tool. If you can't re-scan, use the Split tool to break the document into smaller parts and upload separately. If neither option works for your portal, contact the portal helpdesk — most have an email alternative for genuinely large documents.
Can I compress the same PDF multiple times? ▼
Yes, but with diminishing returns. A second pass of Maximum compression on an already-compressed file may yield 10–20% additional reduction in some cases, but typically much less. More importantly, always compress from the original file if possible — running compression on an already-compressed file produces worse quality than running it once on the original at the same level.