Free online CSV to MDB converter

A legacy Windows application may require an Access .mdb file instead of a delimited text file. Importing the data into MDB makes it available for relational editing in Access and keeps multiple tables in one database file.

What the CSV format is

CSV is a plain-text tabular format used by spreadsheets, accounting systems, database exports, laboratory instruments, and scripts. Each record normally occupies one line, with fields separated by commas; semicolons, tabs, and other delimiters are also common.

CSV stores values, not database structure. It does not reliably preserve field types, primary keys, relationships, indexes, queries, forms, reports, or validation rules. Quoted fields may contain delimiters, line breaks, or escaped quotation marks, so the import process must use the source file's delimiter and text qualifier.

What the MDB format is

MDB is the Microsoft Access database format associated with Access 2000–2003 and supported by later Access versions for compatibility. One MDB file can contain multiple tables, indexes, relationships, saved queries, forms, reports, macros, and validation settings.

MDB is appropriate when a legacy application specifically requires Access 2000–2003 format or when imported tables need to be edited relationally in Microsoft Access. Newer Access databases normally use .accdb, so MDB is mainly a compatibility format. Renaming a CSV file to .mdb does not convert it.

How to convert the file with Microsoft Access

1. Open Access and create a blank database saved as MDB, or open an existing MDB database. In newer Access versions, use File → Save As → Access 2002–2003 Database (*.mdb) if the database was initially created as ACCDB.
2. Choose External Data → New Data Source → From File → Text File.
3. Select the CSV file, choose Import the source data into a new table in the current database, and start the import wizard.
4. Select Delimited, choose the actual separator, enable First Row Contains Field Names when appropriate, and set the text qualifier, normally double quotation marks.
5. Review each column and assign suitable types. Use text for identifiers, postal codes, product codes, telephone numbers, and values whose leading zeros must remain. Set date, integer, decimal, currency, and long-text fields explicitly when automatic detection could be wrong.
6. Select the CSV's character encoding when Access offers that option, especially for accented or non-Latin characters. Choose an existing unique column as the primary key, let Access create an ID field, or select no primary key if the source has no suitable identifier.
7. Complete the import and inspect the table for merged columns, truncated values, changed dates, missing leading zeros, unexpected nulls, and damaged characters. Save the database as MDB if it was not created in that format initially.

Excel can open and clean a CSV, but it does not itself create an MDB database. Use Access for the import and database creation.

Using the built-in converter

You can convert the file on 101convert.com for free without installing software. This is suited to a simple, single-table CSV; because the source contains no Access schema, the result cannot recreate relationships, queries, forms, reports, or validation rules that were not present in the input.

Quality and compatibility limits

• Confirm the delimiter, decimal separator, line endings, text qualifier, and character encoding before importing. A mismatch can merge columns or corrupt non-ASCII characters.
• Check dates manually. A value such as 03/04/2025 may mean March 4 or April 3 depending on regional settings; ISO notation such as 2025-04-03 is less ambiguous.
• Import large integers, account numbers, postal codes, and other identifiers as text when precision or leading zeros matter. Numeric inference can remove zeros or display values in scientific notation.
• MDB databases have an approximately 2 GB maximum file size, and Access also imposes limits on fields, records, and object definitions. Split or reduce datasets that approach these limits.
• Saving as MDB can remove or restrict features that require the newer ACCDB format. Test the result with the legacy application that will open it, and keep the original CSV as a backup.