Is converting DB file 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 DB file 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.

Convert DB file to DuckDB

Upload a .sqlite or .db or .sqlite3 file and get back a DuckDB file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.

1Upload your file

Click to upload or drag and drop

CSV, Excel, SQLite, SQL, DBF (max 10 MB)

2Choose target format

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 a .db file

A .db extension is a habit rather than a format. SQLite uses it, but so do Berkeley DB, thumbnail caches and any desktop application that wanted a generic name, so the first question is what is actually inside yours.

→A .db is routed to the SQLite reader on its extension alone, so one that is not a SQLite database fails to open rather than converting into something wrong.
→You can check first: a SQLite file begins with the text "SQLite format 3" in its first 16 bytes, which head -c 16 yourfile.db will show you.
→DuckDB databases are often saved as .db too, and that one will not open here - rename it to .duckdb or .ddb so it reaches the DuckDB reader instead.

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 DB file

→Declared types, primary keys, NOT NULL constraints and blobs all carry through.
→SQLite reports INTEGER PRIMARY KEY as nullable because it aliases the rowid; the conversion corrects that.
→SQLite type affinity is loose, so a NUMERIC column with no declared scale is given room for decimals rather than being rounded to whole numbers.

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 DB file 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 DB file 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.