Convert PostgreSQL backup to DuckDB
Upload a .backup or .dump 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 PostgreSQL backup
A PostgreSQL backup is not one thing. pg_dump can write plain SQL, a compressed custom-format archive or a tar archive, and all three routinely end up carrying the same .dump or .backup extension.
- →The first five bytes decide: PGDMP means an archive, which is unpacked with pg_restore, and anything else is treated as plain SQL. The extension is never trusted for this.
- →pg_restore is run with --file=- to print SQL to a pipe, so your backup is converted without ever being restored into a live PostgreSQL server: nothing connects to a database and nothing is created.
- →The directory format, pg_dump -Fd, is a folder rather than a file and cannot be uploaded. Re-dump it as -Fc or as plain SQL.
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 PostgreSQL backup
- →Reads pg_dump custom-format archives (.backup, .dump) — pgAdmin's default backup option — as well as plain SQL dumps.
- →Data written as COPY blocks is read, not just INSERT statements. COPY is pg_dump's default, so a reader that only understands INSERT returns your tables with none of their rows.
- →Primary keys declared by a later ALTER TABLE, which is how pg_dump writes them, are preserved.
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 PostgreSQL backup 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 PostgreSQL backup 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.