Free positional file parser

From fixed positions to usable columns.

Turn fixed-width TXT or DAT records into CSV. Your file stays in your browser while you set boundaries, check records and download the result.

Use positions, not guesses about spaces

A positional file might contain names with spaces, numbers padded with zeros and blank fields. Splitting on whitespace would lose those boundaries. FlatFilePro suggests boundaries from consistent runs of spaces across multiple records. Treat them as a starting point: spaces can also occur inside a value, and adjacent fields may have no visible separator. Check the documented starting position and width for each column.

For this 25-character record, extract ID from positions 1–5, Name from 6–17, and Amount from 18–25:

00042Ada Chen    00125.50

With surrounding-space removal enabled, the CSV is:

ID,Name,Amount
00042,Ada Chen,00125.50

Convert a positional file

1. Open the converter and choose Fixed-width → CSV.
2. Choose a TXT or DAT file, or paste records with all spaces intact.
3. Review the suggested columns and their sample values, then rename or adjust them. Existing layouts are preserved; you can also import .ffspec, copy the forward builder’s layout, or add columns manually. Positions begin at 1.
4. Choose whether to remove spaces around extracted values, then preview and download CSV.

In single-layout mode, every input line must match the last field’s ending position. In multiple-type mode, each record must match its type’s configured length. All listed fields are extracted, including fields originally defined as constants. Gaps are ignored, and CSV columns follow the editor’s order. Input may use LF, CRLF or CR line endings; output uses a header row, CRLF and a final newline.

Preserve the characters you need

The trim option removes surrounding spaces only. It does not strip zeros, reformat numbers or check that a constant matches a known value. Turn it off if surrounding spaces are meaningful. Export the positions as .ffspec to reuse them; choose the trim option again next session.

CSV can contain leading zeros, but a spreadsheet may interpret them as numbers. Import identifier columns as Text in Excel. Formula-like source values are preserved, so open only trusted data in spreadsheet software.

ERP and mainframe files: confirm the encoding

This parser handles printable-ASCII records. Enable Multiple row types when headers, details or trailers have different layouts. It does not decode EBCDIC, packed decimal, binary fields or COBOL copybooks, and it does not verify header/trailer totals or record ordering. A file ending in .dat is not necessarily a supported text file. Obtain the format and encoding from the system that produced it.

Limits are 2 MB input, 10,000 records, 100 fields, 10,000 characters per record and 20 MB output. Empty, short, long or non-ASCII records produce a visible error rather than a partial download.

A recurring file deserves a recurring workflow

For occasional work, the browser converter is free. If the same file arrives every night, tell us about the automation you need. The planned FlatFilePro CLI is not available yet.

Need the other direction? See CSV to fixed width.