Compare Two Folders Online (No Installation Required)
Learn how to compare two folders online to find missing files, duplicates, and differences. Free tool, no signup, SHA-256 verified recursive folder comparison.
Why Compare Folders?
Folder comparison is essential for data validation, backup verification, and maintaining organized file systems. Unlike file comparison, folder comparison analyzes entire directory structures, revealing missing files, duplicates, and content differences across thousands of files in seconds.
Lightning Fast
Compare folders with thousands of files in seconds. SHA-256 checksums ensure 100% accuracy.
Privacy-First
Files processed securely in memory and discarded after comparison. Recursive scanning with privacy-first handling.
Key Benefits:
- Data validation: Ensure backups and copies are complete
- Sync verification: Confirm synchronization worked correctly
- Duplicate cleanup: Find wasted storage space
- Audit preparation: Document folder contents for compliance
- Migration verification: Validate data transfers
Step 1: Select Your Folders
Folder Selection Methods
FolderManifest provides two easy ways to select folders:
Method 1: Drag and Drop
- Drag folder from file explorer onto the upload area
- Release to load folder contents
- Repeat for second folder
Method 2: Click to Browse
- Click "Choose Folder" button
- Navigate to desired folder in browser dialog
- Select folder and confirm
Browser Permissions
Modern browsers require permission to read folder contents. When prompted, click "Allow" or "View Files" to grant access. This is a security feature—FolderManifest cannot access folders without explicit permission.
Subfolder Handling
The tool automatically includes all subfolders in comparison. This recursive scanning ensures complete folder tree comparison, not just top-level files.
Pre-Comparison Checklist
- Check folder sizes: Large folders may take longer to process
- Verify folder contents: Ensure you're comparing the right folders
- Ensure permissions: Have read access to all subfolders
- Plan for results: Know how you'll act on findings
Step 2: Choose Comparison Options
What the Tool Compares
File Names
Compares filenames and paths to identify matching files
File Contents (SHA-256)
Cryptographic checksums detect identical files with different names
Folder Structure
Analyzes directory hierarchy and organization
File Metadata
Compares file sizes, modification dates, and types
Understanding Recursive Scanning
Recursive scanning means the tool traverses all subdirectories, building a complete inventory of every file in each folder tree. This includes:
- Deep folder structures: No limit on nesting depth
- All subfolders: Every directory is scanned
- Hidden files: Includes hidden and system files
Network Folders & Cloud Storage
Cloud storage folders (Dropbox, OneDrive, Google Drive) and network folders must be downloaded locally before comparison. The tool cannot directly access cloud or network resources due to browser security restrictions.
Step 3: Review Results
Result Types Explained
Only in A
Files found exclusively in Folder A. These files are missing from Folder B.
Only in B
Files found exclusively in Folder B. These files are missing from Folder A.
Identical
Files with matching SHA-256 hashes. Content is 100% identical, regardless of filename or path.
Different
Files with same path but different SHA-256 hashes. Content differs despite identical names/locations.
Duplicates
Multiple copies of same content (matching SHA-256) within or across folders. Wasted storage space.
Interpreting the Summary
| Metric | What It Tells You |
|---|---|
| File Counts | Total files in each folder, including subdirectories |
| Folder Counts | Number of subdirectories in each folder tree |
| Total Sizes | Combined size of all files in each folder |
| Comparison Statistics | Summary of matches, differences, and duplicates |
Understanding Comparison Results
Missing Files
Why they matter: Missing files indicate incomplete backups, failed syncs, or accidental deletions.
How to locate them: Results show exact paths of missing files. Compare against source to determine which folder is correct.
Recovery options: Restore from backup, re-copy from source, or investigate why files are missing.
Duplicate Files
Wasted space calculation: Duplicates show total wasted storage. Multiply duplicate file size by number of copies minus one.
Cleanup strategies: Keep newest version, keep file in primary location, or review content manually before deleting.
Prevention methods: Regular duplicate detection, organized folder structure, avoid multiple downloads.
Different Content
Version differences: Same filename, different content indicates versioning. Determine which is current.
Corruption indicators: If files should be identical but aren't, one may be corrupted. Compare against known-good backup.
Update verification: After editing files, comparison confirms changes were saved correctly.
Folder Comparison vs Folder Sync
Key Differences
| Aspect | Comparison | Sync |
|---|---|---|
| Modifies Files | No | Yes |
| Can Delete Data | No | Yes |
| Reversibility | Fully reversible | Limited/None |
| Risk Level | None | High |
| Primary Use | Verification | Automation |
| Speed | Fast | Variable |
When to Use Each
Use Comparison When:
- Before syncing: Preview changes, identify conflicts, prevent data loss
- For verification: Backup validation, migration confirmation, integrity checks
- For analysis: Understand differences, find duplicates, track changes
- For documentation: Generate reports, audit evidence, compliance records
Use Sync When:
- Unidirectional backup: One-way replication (A → B) is relatively safe
- Document replication: Copying documents to multiple devices
- Read-only mirrors: Creating backup copies that won't be modified
Dangerous Sync Use Cases (Avoid)
- • Bidirectional sync without versioning
- • Sync as your only backup
- • Automated sync without review
- • Sync between critical systems without testing
Common Use Cases
1. Backup Verification
Before/after backup: Compare backup folder against original to ensure every file is present and identical.
Offsite backup validation: Verify offsite backups match source. Catch corrupted backups before disaster strikes.
Cloud backup checks: After cloud backup completes, download and compare to verify integrity.
2. Data Migration
Server migration: After migrating to new server, compare old and new folders to ensure 100% data transfer.
Cloud migration: Moving from on-premise to cloud? Compare to verify nothing was left behind.
Storage upgrade: Upgrading HDD or migrating to SSD? Verify data integrity after transfer.
3. Folder Sync Validation
Before running sync tools: See what will change before committing to irreversible sync operations.
Post-sync verification: After sync completes, compare folders to confirm it worked correctly.
Conflict resolution: Identify which files changed and need manual conflict resolution.
4. Duplicate Cleanup
Free up storage: Identify duplicate files wasting gigabytes of space. Delete copies safely.
Organize files: Consolidate duplicate folders, eliminate redundancy.
Optimize backups: Remove duplicates before backup to reduce backup size and time.
5. Audit Preparation
Pre-audit snapshots: Generate comparison reports before audits to document folder state.
Change documentation: Compare before/after to show exactly what changed.
Compliance evidence: Prove data integrity to auditors with SHA-256 verification.
Limitations of Free Online Tool
100 Files per Folder
Free tool limited to 100 files per folder. Desktop handles unlimited files.
50MB per Folder
Maximum 50MB total folder size. Desktop processes folders of any size.
No Export Functionality
Results displayed only. Desktop exports PDF, CSV, HTML reports.
One-Time Comparison
Manual comparison only. Desktop automates recurring scans.
Need More Power? Upgrade to Desktop
- ✅ Unlimited files and folders
- ✅ Automated scheduled comparisons
- ✅ Export to PDF, CSV, HTML
- ✅ Email alerts on changes
- ✅ Recursive scanning of entire drives
Frequently Asked Questions
How to compare two folders online?
Upload both folders using the folder selection buttons. The tool will scan all files recursively, calculate SHA-256 checksums, and show you which files are unique to each folder, which are identical, and which have the same name but different content. Results are categorized as "Only in A," "Only in B," "Identical," "Different," and "Duplicates."
What is the difference between folder sync and folder comparison?
Folder comparison shows you the differences between two folders without making any changes. It's a read-only, safe operation used for verification and analysis. Folder sync actually modifies folders to make them identical, which can delete data and is potentially irreversible. Always compare folders before syncing to understand what will change.
Can I compare network folders or cloud storage folders?
Yes! Download folders from cloud storage or network drives to your computer first, then use our tool to compare them. The tool runs through the web app after upload with in-memory processing. Due to browser security restrictions, direct access to network or cloud folders isn't possible, but local copies work perfectly.
How long does it take to compare large folders?
Most comparisons complete within seconds. The time depends on file count and sizes, not folder structure depth. SHA-256 calculation is optimized for speed while maintaining accuracy. Folders with 100 files typically compare in under 10 seconds.
Can I export comparison results?
The free online tool displays results but does not support export. FolderManifest desktop can generate detailed PDF, CSV, and HTML reports for documentation, audit trails, and compliance evidence. Reports include file lists, checksums, and comparison statistics.
What file types are supported in folder comparison?
All file types are supported. The tool compares files by content using SHA-256 checksums, regardless of file extension. This works for documents, images, videos, archives, executables, and any other file type. Binary files, text files, and mixed folders are all handled identically.
What happens if folders have different structures?
The tool handles different folder structures gracefully. It compares files by path relative to each folder root, so you can see which files exist in one folder but not the other, regardless of subfolder organization. Results show exactly which paths differ, making it easy to identify structural differences.
Is it safe to compare folders online?
Yes, when using FolderManifest. Your files are processed server-side with immediate memory cleanup—no storage, no tracking, no retention. Files are held in memory only during comparison and deleted immediately upon completion. HTTPS encryption ensures secure transfer.
Compare Your Folders Now
Ready to compare folders? Try FolderManifest's free online tool—no signup, no installation, instant SHA-256 verified results.
Want to compare individual files? Try Compare Files →