PDF & Tools · 9 min read

PDF Compressor, Merge PDF & Split PDF: Free Tools & Step-by-Step Guide

ToolMiraJune 28, 20269 min read

PDF compression reduces file size by 40–90% by downsampling embedded images — the text itself adds almost no file size; it's always the images. A 15MB presentation PDF can become 1.5MB with minimal visible quality loss.
Merging PDFs combines multiple files into one — essential for submitting multi-document applications (visa, loan, government portals). The page order you set in the tool is the order in the merged file — arrange before merging.
Splitting PDFs extracts specific pages — useful for sharing only relevant sections, reducing email attachment size, or separating a combined report into individual sections.
For all three tasks: PDF24 is the best free offline tool; Smallpdf and ILovePDF are the best free online options with 2-task/day free limits.

Use our free tools to compress PDF file size, merge multiple PDFs into one, or split a PDF into separate pages — all processed securely in your browser.

PDF Compressor: How It Works and What to Expect

Why PDFs Get Large

PDF file size is driven almost entirely by embedded images:

Content Type	Contribution to File Size
Text (even thousands of pages)	< 1%
Vector graphics (charts, logos)	1–5%
Raster images (photos, screenshots)	90–99%
Embedded fonts	1–3%

A 20-page text-only document: typically 100–300KB A 10-page presentation with high-res screenshots: typically 15–50MB

Compression works by resampling embedded images to a lower DPI (dots per inch). 300 DPI (print-quality) images are downsampled to 96–150 DPI (screen-quality) — invisible on screen, significant size reduction.

Compression Levels and Results

Compression Level	DPI Target	Typical Size Reduction	Best For
Low (high quality)	150 DPI	30–50%	Print-quality needed
Medium (balanced)	120 DPI	50–70%	General sharing
High (small file)	96 DPI	70–85%	Email, web upload
Extreme	72 DPI	80–90%	WhatsApp, very small size needed

Example results on a 12MB presentation PDF:

Tool	Output Size	Quality
Smallpdf (strong compress)	1.8MB	★★★★☆
ILovePDF (recommended)	2.1MB	★★★★☆
PDF24 (high compression)	1.6MB	★★★☆☆
Adobe Acrobat (medium)	2.4MB	★★★★★
Ghostscript (screen preset)	1.3MB	★★★☆☆

Best Free PDF Compressor Tools

Tool	Free Limit	Offline?	Best For
Smallpdf	2/day	❌	Quick online use
ILovePDF	File size limit	❌	Quick online use
PDF24	Unlimited	✅ (desktop app)	Regular use, privacy
Ghostscript	Unlimited	✅ (command line)	Developers, batch processing
Adobe Acrobat	Limited free	❌	Best quality control
LibreOffice	Unlimited	✅	Re-export with compression settings

Command line (Ghostscript) for power users: ` gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen \ -dNOPAUSE -dQUIET -dBATCH \ -sOutputFile=output_compressed.pdf input.pdf ` Settings: /screen (72 DPI), /ebook (150 DPI), /printer (300 DPI), /prepress (highest quality)

When Compression Won't Help

Already-compressed PDFs: Running compression twice rarely saves more than 5–10% — most compressors check for this
Text-only PDFs: Almost no size to save — the file is already tiny
Scanned PDFs with high-quality requirements: Legal documents, medical reports — don't compress below readable quality (use minimum 150 DPI for text scans)

Merge PDF: Combining Multiple Files

How to Merge PDFs

Step 1: Upload or select all PDFs to merge Step 2: Arrange the order (drag-and-drop in most tools) Step 3: Download the merged single PDF

Order matters: In loan or visa applications, documents must be in a specific sequence. Set the order before merging — rearranging after requires splitting and re-merging.

Common Use Cases in India

Use Case	Documents Typically Merged
Home loan application	Application form + income proof + bank statements + property documents + KYC
Visa application	Application + photos + itinerary + bank statements + hotel bookings + invitation
Job application portfolio	CV + certificates + experience letters + marksheets
GST return support	Invoices + purchase bills + reconciliation
Court filing	Petition + exhibits + affidavit + supporting documents

Best Free Merge PDF Tools

Tool	Free Limit	Max Files	Page Ordering
PDF24	Unlimited	Unlimited	Drag-and-drop
ILovePDF	File size limit	Unlimited	Drag-and-drop
Smallpdf	2/day	Unlimited	Drag-and-drop
Adobe Online	Limited	100	Drag-and-drop
PDFsam Basic	Unlimited	Unlimited	Manual order

Merging PDFs with different page sizes: Most tools handle mixed A4 + Letter sizes — the output PDF preserves each page's original size. If you need uniform page size in the output, use PDF24's "normalize page size" option before merging.

Split PDF: Extracting Pages

Split Modes

1. Extract single pages: Download each page as a separate PDF file 2. Split by range: Define custom page ranges (e.g., pages 1–5, 6–12, 13–20) 3. Split by bookmark: Automatically split at chapter/section bookmarks 4. Split every N pages: Divide into equal chunks

Common Use Cases

Scenario	Split Method
Sharing only one section of a report	Extract page range
Splitting a combined bank statement into months	Split by page range
Extracting certificates from a marksheet	Extract single pages
Breaking a large textbook PDF into chapters	Split by bookmark
Preparing individual pages for stamp/sign	Extract all pages individually

Page Rotation During Split

Some split tools allow rotating pages during extraction — useful when scanned documents have mixed orientations. PDF24 and Smallpdf both support rotation in the split workflow.

JPG to PDF and Word to PDF: Quick Reference

JPG/PNG/Image to PDF

Method 1 — Browser (fastest): Open Chrome → press Ctrl+P → "Save as PDF" → prints the image as PDF

Method 2 — Online tools: Smallpdf, ILovePDF, PDF24 — drag your image file, download PDF

Method 3 — Windows: Right-click image → Print → Microsoft Print to PDF → Save

Method 4 — Multiple images to one PDF: PDF24 → "Create PDF from images" → upload multiple, arrange, download

Image quality in PDF: The PDF file will embed the image at its original resolution. For print quality: ensure source image is at least 300 DPI. For web/sharing: 150 DPI is sufficient.

Word to PDF (Quick Method)

Windows: File → Export → Create PDF/XPS (not "Print to PDF" — preserves hyperlinks and embedded fonts)

Mac: File → Print → PDF (bottom-left dropdown) → Save as PDF

Google Docs: File → Download → PDF Document (.pdf)

FAQ

What is the maximum file size for online PDF compressors?

Smallpdf free: 5MB per file. ILovePDF free: no stated limit but slows above 50MB. PDF24 online: 200MB. For files above 200MB: use PDF24 desktop app or Ghostscript locally — no size limits.

Why is my PDF still large after compression?

Common causes: (1) The PDF contains vector graphics, not raster images — these cannot be compressed this way, (2) The PDF was already compressed, (3) The images are embedded as lossless PNG — convert to JPEG first for more compression. Re-open the PDF in LibreOffice and re-export with JPEG compression for images.

Can I merge password-protected PDFs?

No — you must remove the password first (see PDF compressor tools that also include unlock features). Most merge tools will prompt you for the password during upload; if you don't have it, the file cannot be merged.

Will merging PDFs reduce quality?

No — merging PDFs is lossless. The pages are copied directly from the source files without re-encoding. Quality is only lost if you compress during or after merging.

Try the Free PDF Compressor

Use ToolMira's calculator — no signup, no ads, works on mobile.

Open PDF Tools →

Written by Ananya Menon

Ananya writes about personal finance, tax, and investing for ToolMira, breaking down India's money rules into plain language with worked examples.

Disclaimer: This article is for educational purposes only and does not constitute financial, investment, or professional advice. Please consult a qualified professional before making any decisions based on this content.