Convert TSV to DuckDB
Upload a .csv or .tsv 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 a .tsv file
Tab-separated files come out of database shells, BI exports and anything that had to avoid commas inside its own values. They go through the same reader as CSV - the tab simply wins the separator sniff - so there is nothing to configure.
- →The extension is what routes an upload, and only .csv and .tsv reach this reader. A tab-separated file saved as .txt or .tab is not recognised, so rename it before uploading.
- →Because the separator is detected from the content and not the extension, a file named .csv that is really tab-separated is still read correctly.
- →Quoting rules still apply: a double quote opening a field is treated as a quote character, which is worth knowing for exports that never intended to quote anything.
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 TSV
- →Leading zeros are preserved. A column containing 01234 is kept as text, never turned into the number 1234.
- →An empty cell becomes NULL, not an empty string — the two mean different things once the data is in a database.
- →Dates are only treated as dates when the format is unambiguous. 03/04/2025 could be March 4th or April 3rd, so it stays text unless another value in the column settles it.
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 TSV 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 TSV 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.