Whether you're a student highlighting research papers, a designer providing feedback on mockups, or just someone who prefers digital annotation over printing everything out (hello, environment!), having the right PDF drawing tool makes all the difference.

I've spent way too many hours testing PDF annotation apps, so you don't have to. Here are the 5 best options in 2025, ranging from the industry heavyweight to some surprisingly capable underdogs.

1. Adobe Acrobat Pro DC - The Industry Standard (That'll Empty Your Wallet)

Price: $12.99-19.99/month
Best for: Professional environments with deep pockets

Adobe Acrobat is like that expensive restaurant everyone talks about - yes, it's good, but is it really worth what you're paying?

The Good:

• Every feature you could ever want (and probably 50 you don't need)

• Industry standard - works with everyone's workflows

• Excellent OCR and text editing capabilities

• Rock-solid reliability

The Not-So-Good:

• That subscription fee will haunt your monthly budget

• Overkill for basic annotation needs

• Can feel sluggish on older devices

• Creative Cloud dependency

Verdict: If you're editing PDFs professionally all day and your company is paying, go for it. For everyone else? Keep reading.

2. Xodo - The Mobile Crowd Favorite

Price: Free (with premium options)
Best for: Mobile-first users and teams

Xodo has built quite a following, especially among students and mobile users. It's like the Swiss Army knife of PDF apps - compact, reliable, and gets the job done.

The Good:

• Genuinely free version with solid features

• Great mobile experience with touch optimization

• Real-time collaboration through Xodo Connect

• Clean, intuitive interface

The Not-So-Good:

• Limited advanced drawing tools

• Free version has some restrictions

• Occasional sync issues with cloud storage

• Desktop version feels like an afterthought

Verdict: Solid choice for basic annotation needs, especially if you're primarily on mobile. But don't expect to create digital masterpieces.

3. PDF Annotator - The Windows Desktop Champion

Price: Around $99 one-time purchase
Best for: Windows users who want desktop-native performance

PDF Annotator is that reliable friend who's been around forever and just works. It's particularly popular in educational and business settings.

The Good:

• Native Windows performance

• Excellent for presentations and meetings

• One-time purchase (no subscriptions!)

• Great tablet PC integration

The Not-So-Good:

• Windows only (sorry, Mac and Linux folks)

• Interface feels dated compared to modern alternatives

• No browser or mobile version

• Limited collaboration features

Verdict: If you're a Windows user who values desktop apps and hates subscriptions, this is your jam. Just don't expect it to win any design awards.

4. Smallpdf - The Quick Web Solution

Price: Free (with limitations), $9/month for Pro
Best for: Quick, one-off annotation tasks

Smallpdf is like that corner coffee shop that does one thing really well - simple, fast PDF tasks without the fuss.

The Good:

• No installation required - works in any browser

• Clean, modern interface

• Quick processing for simple tasks

• Decent free tier

The Not-So-Good:

• Limited drawing tools and customization

• File size restrictions on free tier

• No offline capabilities

• Basic annotation features compared to dedicated apps

Verdict: Great for quick annotation jobs when you don't want to install anything. But if you're doing serious PDF work regularly, you'll quickly outgrow it.

5. LeedPDF - The Game Changer (And It's Actually Free)

Price: Completely free and open-source
Best for: Everyone who values privacy, features, and not paying monthly fees

Here's where things get interesting. LeedPDF isn't just another PDF tool - it's what happens when developers actually listen to what users want instead of what shareholders demand. And unlike every other option on this list, you get to choose your preferred experience: native desktop app (Windows available now, Mac in development) or browser-based convenience. Why should you have to compromise?

The Good:

• Actually free - No hidden costs, no "premium" features locked away

• Privacy-first approach - Your PDFs never leave your device (seriously!)

• Works everywhere - Browser-based but feels native on any device

• Advanced drawing tools - Pressure-sensitive drawing with Apple Pencil support

• Professional feature set - Text annotations, shapes, sticky notes, smart eraser

• Accessibility champion - WCAG AAA compliant (7.06:1 contrast ratios!)

• No account needed - Just open and start annotating

• Open-source - Built with SvelteKit, fully transparent

• Progressive Web App - Works offline after first visit

• Universal device support - Responsive design from phones to desktops

The Kinda-Good-But-Worth-Mentioning:

• Being browser-based means it needs an internet connection for first load

• Open-source means updates depend on community contributions

• Newer player in the market (though built on solid tech)

What Makes LeedPDF Different:

Privacy That Actually Matters: While other apps talk about security, LeedPDF walks the walk. Your documents are processed entirely on your device using modern browser technologies. No uploads, no cloud storage you don't control, no wondering where your sensitive documents end up.

Genuinely Free Forever: Not "free with premium features" or "free trial then pay up." Actually free. The AGPL open-source license means it stays that way.

Modern Web Technology Done Right: Built with SvelteKit and PDF.js, LeedPDF delivers performance that rivals native apps while working universally across devices. The responsive design means it's equally comfortable on your iPhone or your 4K desktop monitor.

Accessibility Without Compromise: Most apps treat accessibility as an afterthought. LeedPDF is WCAG AAA compliant from day one, with proper keyboard navigation, screen reader support, and contrast ratios that exceed standards.

Drawing Tools That Actually Work: Pressure-sensitive drawing, multiple brush sizes, smooth rendering, Apple Pencil optimization - all the features you'd expect from premium apps, without the premium price tag.

Verdict: Unless you have very specific enterprise requirements or are locked into Adobe's ecosystem, LeedPDF is simply the best choice available. It's what PDF annotation should have been from the beginning.

The Bottom Line

Here's the thing - most people don't need to pay monthly subscriptions to annotate PDFs. The technology has evolved enough that browser-based solutions can deliver professional results without the traditional compromises.

Choose Adobe Acrobat if: Your company pays for it and you need every possible feature.

Choose Xodo if: You're primarily on mobile and need basic collaboration.

Choose PDF Annotator if: You're on Windows, hate subscriptions, and want desktop-native performance.

Choose Smallpdf if: You somehow haven't discovered LeedPDF yet and enjoy paying for basic features.

Choose LeedPDF if: You want the best features, care about privacy, prefer not to pay monthly fees for basic functionality, and appreciate when software is built with users (not shareholders) in mind.

The PDF annotation landscape has changed dramatically in the past few years. Browser technologies have matured, privacy concerns have grown, and users are tired of subscription fatigue. LeedPDF represents what's possible when you prioritize user needs over revenue extraction.

Try them out for yourself, but don't say I didn't warn you when you find yourself wondering why you ever paid for PDF annotation in the first place.

Want to try LeedPDF for yourself? Head over to leed.my and start annotating immediately - no download, no account, no credit card required. Because that's how software should work.