Is converting DDB to Excel 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 DDB data keep its types in Excel?

Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real Excel 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 DDB to Excel

Upload a .duckdb or .ddb file and get back a Excel 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 Excel

Generated from the converter's own Excel type mapping — this is what it actually emits, not an example.

Your data	Excel type
Whole number	number
Decimal (money)	number
Floating point	number
True / false	boolean
Date	date
Date and time	date
Short text	text
Long text	text
Binary data	hex text

Working from a .ddb file

.ddb is the short form of the DuckDB extension, and DuckDB itself does not care what you call a database file. The uploader does: it routes on the extension alone, so the name you saved under decides which reader ever sees the file.

→.ddb and .duckdb both reach the DuckDB reader and are read identically. Nothing inside the file records which of the two you chose - the storage version is in the header, the name is not.
→One file is this format's whole promise, so make sure it really is one file before you send it: closing the DuckDB CLI cleanly, or running CHECKPOINT first, folds the write-ahead log back into the database itself.
→A file with no extension at all, which DuckDB is perfectly happy to create, is not recognised as anything and is refused before it is read.

What opens the converted workbook

Choosing Excel as the target puts no copy of Excel anywhere in the process: the workbook is assembled on the server by a library and handed over finished. What that library writes is what decides how the result behaves when you open it.

→The output is .xlsx, the OOXML format, and only that. There is no .xls option, so a machine that can open nothing newer than Excel 97-2003 needs the CSV target and a save from there instead.
→Values are the only thing written. No formulas, no macros, no charts, no column widths, no frozen header row - which is why the first thing most people do with it is widen a column. If Excel opens it in Protected View, that is the mark of the web on a downloaded file rather than anything in the workbook.
→A conversion is capped at a million rows across all of its tables, and a worksheet holds 1,048,576, so no table can ever arrive too tall for the sheet it is being written into.

Reading DDB

→Types, primary keys and NOT NULL constraints are read from the database.
→The file is opened read-only, so your upload is never modified or upgraded in place.

Writing Excel

→One file per table. Booleans stay booleans and numbers stay numbers.
→Excel has no fixed-point type, so decimals become numbers — use a database target if exactness matters.

What you get

A ZIP containing <table>.xlsx. If anything about your data needed a judgement call, a _warnings.txt explains it.

Questions

Is converting DDB to Excel 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 DDB data keep its types in Excel?: Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real Excel 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.