Free PDF Converter
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Why convert files to PDF?

PDF is the universal document format for sharing, printing, and archiving. Whether you're sending a resume to an employer, submitting an assignment to a university portal, mailing a contract to a client, or uploading a report to a government website — PDF is almost always the required format. Here's why:

• Consistent appearance everywhere — PDFs look identical on Windows, Mac, Linux, iPhone, Android, and in every browser. Your formatting won't break when the recipient opens it.
• Locked content — PDFs are much harder to edit accidentally, making them the standard for contracts, invoices, and final deliverables.
• Universal compatibility — Not everyone owns Microsoft Office or Excel, but every device can open a PDF with free built-in readers.
• Smaller file sizes — Converted PDFs are often more compact than the original DOCX or PPTX, making them easier to email or upload.
• Professional presentation — Sending a resume, quote, or proposal as a PDF looks more polished than sending a raw editable file.

What makes PDFduck different from other PDF converters?

Most online PDF converters — Smallpdf, iLovePDF, PDF24, Adobe Acrobat online — work the same way: you upload your file to their server, they convert it in the cloud, then you download the result. That model has three problems:

• Privacy risk — Your file leaves your device. It passes through their servers, may be temporarily stored, and in some cases is used for analytics or AI training.
• Usage limits — Most free tiers cap you at 2–3 conversions per day. Need to batch convert 20 files? You hit a paywall fast.
• Required sign-ups — Even "free" converters often ask for your email, verify your account, or force you to install browser extensions.

PDFduck takes a different approach. The entire conversion happens inside your browser using JavaScript libraries that run on your device. Your file never reaches any server. We literally cannot see what you're converting because we're not involved in the conversion at all.

PDFduck vs. Smallpdf vs. iLovePDF: honest comparison

Here's how PDFduck stacks up against the most popular free PDF converters:

PDFduck is built for people who just want to convert their files quickly, privately, and without dealing with paywalls or account creation. If you need advanced features like OCR, electronic signatures, or form filling, tools like Adobe Acrobat or Smallpdf Pro might suit you better. For everyday PDF conversion, PDFduck is the simpler, more private choice.

When should you use PDFduck?

PDFduck is ideal for these common scenarios:

• Job applications — Convert your CV or resume from Word to PDF before submitting. Employers and applicant tracking systems (ATS) prefer PDFs because they render consistently.
• University assignments — Most learning management systems (Moodle, Canvas, Blackboard) require PDF uploads. Convert your DOCX reports in seconds.
• Business documents — Invoices, quotes, proposals, and contracts look more professional and are harder to accidentally edit when sent as PDF.
• Photo to PDF — Combine multiple JPG or PNG images (receipts, IDs, scanned pages) into a PDF for emailing or archival.
• Presentations for review — Convert PowerPoint decks to PDF so reviewers can read them without needing PowerPoint installed.
• Financial records — Convert Excel spreadsheets to PDF for audit trails, year-end archiving, or sharing with accountants.
• Confidential documents — Medical records, legal papers, and anything you don't want to upload to a third-party server.

Which PDF converter do you need?

PDFduck offers dedicated pages for each file format with detailed guides and format-specific tips:

• Word to PDF — Convert DOCX documents while preserving fonts, tables, images, headings, and hyperlinks. Best for resumes, reports, contracts, and letters.
• JPG to PDF — Turn single images or multiple photos into a PDF document. Perfect for scanned receipts, ID photos, or photo collections.
• PNG to PDF — Convert transparent and lossless PNG images into a shareable PDF document. Great for screenshots, logos, and diagrams.
• Excel to PDF — Convert XLSX spreadsheets with all sheets, tables, and number formatting intact. Great for financial reports, data snapshots, and audit trails.
• PowerPoint to PDF — Turn PPTX presentations into shareable PDF slide decks. Ideal for sending decks to reviewers who don't have PowerPoint.

Each dedicated page includes format-specific FAQ, tips, and guidance to help you get the best conversion result for your file type.

How browser-based PDF conversion works

Traditional online converters follow a simple but privacy-unfriendly flow: upload your file → convert on server → download result. PDFduck removes the server entirely. When you drop a file onto the page, modern browser JavaScript libraries take over:

• DOCX files are parsed by Mammoth.js, which reads the Office Open XML format directly in your browser and extracts the content and formatting.
• XLSX files are handled by SheetJS, a battle-tested spreadsheet library that reads Excel workbooks client-side.
• PPTX files are unzipped with JSZip and slide content is extracted directly from the underlying XML.
• JPG and PNG images are read natively by the browser's built-in image decoders — no library needed.
• All extracted content is then rendered into a PDF using jsPDF and html2canvas, which generate the final PDF file entirely on your device.

The result: a PDF generated without any network requests after the page loads. You could even disconnect your internet after loading pdfduck.app and the conversion would still work.

Tips for the best PDF conversion results

• Use standard fonts in your Word and PowerPoint files — Arial, Calibri, Times New Roman, and Georgia render most reliably. Exotic custom fonts may fall back to defaults.
• Keep image resolution reasonable — Very high-res images in DOCX or PPTX slow down conversion and produce huge PDFs. 150–300 DPI is usually enough.
• Accept track changes in Word before converting — unaccepted edits may appear strangely in the PDF output.
• Close spreadsheet formulas that have errors (#REF!, #N/A) before converting XLSX files. The PDF will show the error text otherwise.
• Flatten complex PPTX animations — PDFs are static, so any on-click animations or transitions obviously won't carry over. Your final slide state is what renders.
• Save DOCX, not DOC — PDFduck supports the modern DOCX format only. If you have an old .doc file, save it as .docx in Word or Google Docs first.
• Remove passwords first — Encrypted or password-protected files cannot be converted. Remove protection in the source app before uploading.