MS Access Validator
Drop any .mdb or .accdb file to instantly inspect its structure. Verifies the Jet/ACE file signature, detects the Access version, checks for password encryption, reports page size, estimates page count, and flags known corruption indicators. Nothing leaves your browser.
Access Database File
Drop a .mdb or .accdb file here, or
Supports .mdb and .accdb files up to 500 MB
⛔
Wrong file type — only .mdb or .accdb files are supported. You dropped a file.
Validation Errors
Warnings
✓ Valid Access Database
Database Header Details
File Header Hex Dump (first 80 bytes)
How It Works
1
Drop your Access fileDrag it onto the drop zone or click "browse" to select it. Supports both the legacy .mdb (Jet) and modern .accdb (ACE) formats.
2
Binary header analysisThe validator reads the raw binary header, checks the Jet/ACE magic signature, decodes the version byte, reads page size, detects encryption flags, and scans for known corruption markers.
3
Review the reportGet a pass/fail result with full stats: Access version, format engine, page size, estimated page count, encryption status, file size, and an annotated hex dump of the header.
What Gets Validated
- File signature — checks the 4-byte magic number
00 01 00 00that every valid Jet/ACE file must begin with. - Format string — reads the ASCII identifier at offset 4:
Standard Jet DBfor .mdb files orStandard ACE DBfor .accdb files. - Version detection — decodes the version byte at offset 0x14 to identify Access 97, 2000, 2002–2003, 2007, 2010, 2013, or 2016/2019/365.
- Page size — reads the page size from the header (2 KB for Jet 3, 4 KB for Jet 4 / ACE) and validates it against known-good values.
- Encryption / password protection — inspects the encryption flags and password bytes in the header to detect whether the database requires a password to open.
- File size alignment — confirms the file size is a multiple of the detected page size, which is required for an intact database.
- Minimum size check — flags files smaller than a single page as structurally incomplete or truncated.
- Hex dump — renders an annotated hex view of the first 80 bytes so you can visually inspect the raw header.
🔒 Privacy & Security
All validation is performed locally using the Web File API and the FileReader API. Your database file is never sent to a server. Suitable for sensitive business data, customer records, or any private Access database.