5 Best Free Mobile Scanner Apps for PDF Documents (2024)

Your smartphone is a powerful document scanner — you just need the right app. We tested five of the top free scanning apps on both iOS and Android, scanning a variety of documents from crumpled receipts to multi-page contracts.

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What Makes a Good Mobile Scanner App?

Before diving in, here’s what we evaluated:

• Edge detection accuracy — does it find document edges automatically?
• Image quality — does it correct lighting, remove shadows, straighten?
• OCR capability — can it extract text from scans?
• Multi-page handling — easy to add pages and reorder?
• Export formats — PDF, JPG, searchable PDF?
• Free tier limitations — watermarks, page limits, storage caps?

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1. Adobe Scan — Best Overall

Platform: iOS & Android | Free (with Adobe account)

Adobe Scan is the most polished scanner app available, full stop:

• Automatic edge detection is flawless on flat, lit surfaces
• Auto-capture triggers when the document fills the frame — no tapping
• Auto-enhance removes shadows, adjusts contrast, improves legibility
• Built-in OCR creates searchable PDFs
• Cloud sync to Adobe Document Cloud
• Multi-page support with easy reordering

Free tier limits: Unlimited scans, but full OCR and annotation require Adobe Acrobat subscription.

Best for: Users in the Adobe ecosystem, anyone who needs the most reliable automatic capture.

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2. Microsoft Lens — Best for Microsoft/Office Users

Platform: iOS & Android | Completely Free

Microsoft Lens (formerly Office Lens) has specialized modes for different document types:

• Document mode — for single pages
• Whiteboard mode — corrects perspective for angled shots of whiteboards
• Business Card mode — extracts contact info automatically
• Photo mode — for general photography

Integration: Exports directly to OneDrive, OneNote, Word, and PowerPoint. The Word export is particularly impressive — it actually converts scanned text to editable Word content.

Free tier: Completely free with no limitations (Microsoft account required for cloud sync).

Best for: Anyone in the Microsoft ecosystem, students who take whiteboard photos.

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3. CamScanner — Best for Power Features (Free Tier OK)

Platform: iOS & Android | Freemium

CamScanner pioneered the mobile scanning category and remains feature-rich:

• Smart auto-crop and perspective correction
• Magic color mode (removes lines from lined paper)
• ID/passport/business card scanning
• QR/barcode reading
• Batch scanning with auto-advance

Free tier: Scans saved with a small watermark at bottom. No page limits. 200MB cloud storage.

Paid tier: Removes watermarks, adds OCR export, more storage.

Best for: Users who need advanced features and can tolerate the watermark on free tier.

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4. Apple Notes Scanner (Built-in iOS) — Best for Simplicity

Platform: iOS only | Completely Free

For iPhone users who don’t want to install anything, the Notes app scanner is excellent:

• Open Notes → New Note → Camera icon → Scan Documents
• Auto-detects and captures — fast and accurate
• Multi-page support
• Saves to iCloud automatically

It doesn’t have OCR or advanced features, but for archiving documents and sharing PDFs, it’s all most users need.

Best for: iPhone users who want zero friction, no extra apps.

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5. Google Drive Scan — Best for Android

Platform: Android | Completely Free

Google Drive’s built-in scan (+ button → Scan) is the equivalent of Apple Notes for Android:

• Decent edge detection
• Auto-captures when still
• Saves directly to Google Drive as PDF
• Basic but functional

The biggest advantage: no extra app needed on Android, and it integrates with Google’s ecosystem.

Best for: Android users who want the simplest possible workflow.

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Feature Comparison

App	Auto-Capture	OCR	Watermark-Free	Multi-Page	Best Platform
Adobe Scan	✓	✓	✓	✓	Both
Microsoft Lens	✓	✓ (to Word)	✓	✓	Both
CamScanner	✓	Paid	✗ (free)	✓	Both
Apple Notes	✓	✗	✓	✓	iOS only
Google Drive	Partial	Via Docs	✓	✓	Android

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Our Recommendation

• iPhone users: Apple Notes for quick scans; Adobe Scan when you need OCR
• Android users: Google Drive for quick scans; Microsoft Lens for the best free all-rounder
• Both platforms: Adobe Scan is the top choice for professional use

Combined with AltoUnlockPDF for post-processing (adding OCR, compressing, merging), any of these apps will handle your mobile scanning needs effectively.