MDB file: what it is and how to open one

An .mdb file is a Microsoft Access database: tables of records, and often the queries, forms and reports built on them, all in one file. It was Access's standard format up to Access 2003 (Access 2007 replaced it with .accdb), so most .mdb files people are handed today come from an older system, a vendor export or an archive. You do not need Access to read one.

Which program opens an .mdb file

• Windows, with Microsoft Access: double-click it. Access 2007 and later open .mdb files from Access 2000 onward. Files from Access 97 need Access 2010 or earlier (why).
• Windows, without Access: Excel can import the tables (Data → Get Data → From Database → From Microsoft Access Database) if the Access Database Engine is installed; if it is not, Excel stops with The 'Microsoft.ACE.OLEDB.12.0' provider is not registered. The free Access Runtime runs finished Access applications but hides the navigation pane, so it is a poor way to simply look at tables.
• Mac: there has never been an Access for Mac. The options are a Chrome extension, mdbtools from Homebrew on the command line, or Windows in a virtual machine (details).
• Chromebook: a Chrome extension, or mdbtools under Linux (details).
• Linux: mdbtools, packaged by most distributions: mdb-tables file.mdb lists the tables, mdb-export file.mdb TableName > table.csv exports one.
• In Chrome on any of these computers: AccessLens opens .mdb files from Access 97 to 2003 (and .accdb files from 2007 to 2019) in a browser tab. Browse and search every table, and export a table to CSV or the whole database to Excel, SQLite or a SQL script. Nothing is uploaded.

Microsoft Access has no phone or tablet version, so open the file on a computer. Every viewer side by side, with prices and which ones upload your file: MDB viewers compared.

Getting the tables into Excel or Google Sheets

An Access database holds many tables, and a spreadsheet holds one table per sheet. Excel's import on Windows (it needs the Access Database Engine) and mdb-export both move one table at a time. AccessLens does either: pick a table and use Export → This table → CSV, or use Export → All tables → Excel workbook to get every table in one .xlsx file, one sheet per table. Excel, Numbers and Google Sheets open both.

Exporting all tables at once is free for databases of up to 20 tables and 50,000 rows in total; bigger databases need the optional one-time Pro licence for it. Exporting one table to CSV is free at any size.

Before you upload it to an online viewer

Online MDB viewers come in two kinds. Some upload the file to their server and convert it there, usually with a size limit; others read it inside your browser. For anything confidential (customer, HR, financial or medical records) find out which kind a site is before you use it.

AccessLens is in the second group by construction: it requests no permissions at all, network included, so it has no way to send the file anywhere. The empty permissions list is visible on its store page.

Is it really an Access file?

Other programs sometimes reuse the .mdb extension for formats of their own. To check, open the file in Notepad or any text editor: a genuine Access .mdb shows Standard Jet DB at the very start (an .accdb shows Standard ACE DB). If you see neither, no Access viewer can read it; you need the program that created it.

• A small .ldb file next to the database is a lock file that Access creates while the database is open. It holds no data.
• ArcGIS personal geodatabases really are Access .mdb files, so Access-compatible tools can read their attribute tables. The map shapes themselves are stored in a binary format that only GIS software can draw.

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