Convert MS Access to DuckDB
Upload a .mdb or .accdb or .mde file and get back a DuckDB file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.
Click to upload or drag and drop
CSV, Excel, SQLite, SQL, DBF (max 10 MB)
How your data is typed in DuckDB
Generated from the converter's own DuckDB type mapping — this is what it actually emits, not an example.
| Your data | DuckDB type |
|---|---|
| Whole number | BIGINT |
| Decimal (money) | DECIMAL(10,2) |
| Floating point | DOUBLE |
| True / false | BOOLEAN |
| Date | DATE |
| Date and time | TIMESTAMP |
| Short text | VARCHAR |
| Long text | VARCHAR |
| Binary data | BLOB |
Working from an Access database
An Access file is an application as much as a database: tables, but also queries, forms, reports, macros and VBA modules. Only one of those is data, and only that one is something a conversion can carry anywhere else.
- →The tables convert. Saved queries, forms, reports, macros and modules are not data and do not appear in the output - re-create a query as a view in the target if you need it.
- →Access types map to fixed shapes: Currency to DECIMAL(19,4), matching Access's own four fixed decimal places, Decimal to DECIMAL(18,6), Long Integer to a 32-bit integer, Byte and Integer to 16-bit, Memo and Hyperlink to text, OLE and Binary to a blob.
- →If the file cannot be opened at all - a database password, or real damage - the conversion stops with the underlying tool's own error instead of handing you a partial result.
Decimals and text in the .duckdb file
DuckDB takes the source's declared types more nearly unchanged than any other target here, which makes the two places where it cannot the things worth reading: the width of a decimal, and the length of a string.
- →DECIMAL tops out at 38 digits, so a wider source column is clamped rather than refused: an Oracle NUMBER(50,10) is created here as DECIMAL(38,10), and the scale is never allowed to grow past the precision holding it.
- →A decimal that declared no scale gets six places for its fraction rather than none, inside that same rule: a source precision of 10 becomes DECIMAL(10,6), one of 5 becomes DECIMAL(5,5), and one that declared no precision either becomes DECIMAL(18,6).
- →Strings become VARCHAR with no length attached to them. DuckDB's VARCHAR is unbounded, so no column has to be sized in advance and no row can be turned away for being longer than the column it goes in.
Reading MS Access
- →Dates are exported in ISO form, avoiding the ambiguous 12/02/21 that Access tools produce by default.
- →NULL and the empty string stay distinct.
- →Access can hold dates outside the range it can represent. Those become NULL and the conversion tells you, rather than dropping them silently.
- →Requires mdbtools on the server; if it is unavailable you get a clear error rather than a partial conversion.
Writing DuckDB
- →A real .duckdb file, not a script — open it straight away with the DuckDB CLI.
- →DuckDB has genuine DECIMAL and BOOLEAN types, so nothing is flattened on the way in.
What you get
A ZIP containing database.duckdb. If anything about your data needed a judgement call, a _warnings.txt explains it.
Questions
- Is converting MS Access to DuckDB free?
- Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.
- Will my MS Access data keep its types in DuckDB?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real DuckDB types rather than everything becoming text. The mapping table above shows exactly what you get.
- Do you store my file?
- No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.