Android users have no shortage of document scanner options — but not all of them are created equal. (On Apple devices? See our guide to the best document scanner app for iPhone.) The difference between a good scanner app and a great one comes down to four things: scan quality, what happens to the file after you scan it, how private your documents stay, and what you can do with the PDF once it's created.
Here's an honest comparison of the best options available in 2026.
What makes a great Android document scanner?
Before looking at specific apps, these are the criteria that actually matter:
- Edge detection quality: Does the app accurately find the document boundary and correct perspective automatically, or do you need to manually drag corner handles every time?
- PDF output: Does it produce a proper, searchable PDF, or just a JPEG image renamed as PDF?
- Storage and privacy: Where does the file go after scanning? Is it encrypted? Can the provider read it?
- Post-scan features: Can you sign, annotate, or extract information from the PDF once it's scanned?
- Free tier limits: How many scans can you do for free, and are there watermarks on free outputs?
The best Android document scanner apps compared
| App | Edge detection | Free storage | Encrypted? | AI features | PDF signing | Watermarks |
|---|---|---|---|---|---|---|
| PrimeDocu | Excellent | 1 GB | AES-256-GCM zero-knowledge | Yes — summarise, translate, extract | Yes — free | None |
| Google Drive (built-in) | Good | 15 GB (shared) | In transit only (Google can read) | Google Lens OCR only | No | None |
| Microsoft Lens | Excellent | 5 GB OneDrive | In transit only (Microsoft can read) | OCR, OneNote integration | No | None |
| Adobe Scan | Very good | 25 free scans/month | Adobe cloud (Adobe can read) | OCR only (free) | Adobe Acrobat required | None (free tier) |
#1 — PrimeDocu
PrimeDocu is a browser-based document management app — meaning it works on any Android device without requiring a Google Play download. This is especially useful on work-managed devices where app installation is restricted.
Scan quality: The edge detection engine automatically identifies document boundaries and applies perspective correction. Even if you scan at a slight angle, the output PDF is corrected to appear flat and straight.
Privacy: This is where PrimeDocu is genuinely different from every other app in this list. Documents are encrypted with AES-256-GCM, and the encryption key is stored in the Android Keystore on your device. PrimeDocu's servers store an encrypted blob — they cannot read your documents. For sensitive documents (passport, medical records, financial statements), this matters — and it's exactly what makes a scanner trustworthy when you're trying to go paperless at home.
After scanning: Once your document is in PrimeDocu, you can sign it, use AI to summarise or translate it, extract key dates, and organise it in folders. The free plan includes 10 AI credits per month and unlimited PDF signing — with no watermarks.
#2 — Google Drive built-in scanner
If you just need to scan a document with your phone and you're happy for it to go directly into Google Drive, the built-in scanner in the Google Drive app is fast and produces clean results. Tap the + button, tap Scan, and you're done.
Limitations: Files saved to Google Drive are readable by Google. There's no AI analysis beyond basic OCR, and you can't sign PDFs from within Drive. For documents you're comfortable storing unencrypted in Google's servers, it's a perfectly capable free tool.
#3 — Microsoft Lens
Microsoft Lens has excellent edge detection and OCR — arguably the most accurate text extraction of any free scanner. It integrates seamlessly with OneNote and saves to OneDrive.
Best for: Scanning whiteboards, business cards, and text-heavy documents that you want to search later via OneNote. If you're already in the Microsoft 365 ecosystem, Lens is a natural choice.
Limitations: Microsoft's cloud storage is not zero-knowledge — Microsoft can access your files. There's no built-in PDF signing or AI document analysis beyond OCR.
#4 — Adobe Scan
Adobe Scan produces clean scans with solid perspective correction and pushes files to Adobe's cloud. The free tier is limited to 25 scans per month.
Best for: Users who already have Adobe Creative Cloud or Acrobat subscriptions, as the scanned PDFs integrate smoothly with those tools for advanced editing and signing.
Limitations: Signing requires Adobe Acrobat, which is $23.99/month. The 25 free scans per month limit is frustrating for high-volume use. Adobe has access to your stored documents.
Which should you choose?
The answer depends on what you prioritise:
- Best overall for sensitive documents: PrimeDocu — zero-knowledge encryption, AI features, PDF signing, no watermarks, all free.
- Best for quick workflow into Google ecosystem: Google Drive scanner — fastest if you already live in Google Workspace.
- Best OCR and Microsoft integration: Microsoft Lens — superior text recognition, ideal for OneNote users.
- Best for Adobe power users: Adobe Scan — if you already pay for Acrobat, it's a natural fit.
Frequently asked questions
What is the best free document scanner for Android?
For privacy and features combined, PrimeDocu is the strongest free option — AES-256 encrypted storage, AI document analysis, PDF signing, and 1 GB storage with no watermarks. For quick scan-and-save-to-Drive, Google Drive's built-in scanner is fast and free. For OCR quality specifically, Microsoft Lens is excellent. The right choice depends on what you do with the scan after you take it.
Can I scan documents without an app on Android?
Yes — Google Drive has a built-in document scanner accessible from the main app. Tap the + button and select Scan. This saves directly to your Google Drive. You can also use your Android camera app's built-in Google Lens feature to capture and convert documents. However, neither option provides encrypted storage or AI analysis.
Which Android scanner app has the best privacy?
PrimeDocu offers the strongest privacy of any scanner in this comparison. Documents are encrypted with AES-256-GCM and the encryption key is stored in the Android Keystore on your device — PrimeDocu's servers cannot read your files. Google Drive, Microsoft OneDrive, and Adobe cloud storage are all encrypted in transit and at rest, but the provider has access to your files and can scan them for content.