Convert Delimited Rows into an Explicit Fixed-Width Layout

How to Use This Tool

Map columns to declared widths without guessing a schema or truncating overflow silently. Convert pasted delimited rows into fixed-width text using explicit column widths, rejecting records that would be silently truncated.

The exact task

A quick delimiter replacement cannot preserve column boundaries, and silent truncation can turn distinct identifiers into the same fixed-width value. This page transforms only delimited rows, column widths, single-character delimiter. It does not fetch a remote resource, inspect an account, guess an omitted schema or claim that syntactically tidy output is operationally safe.

Transformation rule

Split each record by one declared delimiter, require exactly one width per column, reject overflow, right-pad each value with spaces and concatenate columns. The default fixture is executable, so a future change that alters punctuation, ordering, escaping or validation will fail before publication. Try a small representative sample first and compare every generated token with the source.

How to interpret the output

Inspect spaces with a monospace editor and confirm encoding, byte width and line endings in the destination system before processing a full file. The supporting outputs—converted row count, record character width—make the transformation auditable rather than presenting one opaque block to copy.

Assumptions

• Input fields do not contain the delimiter.
• Widths are character counts, not encoded byte counts.
• Values are left-aligned and padded on the right.

Keep the original text unchanged until the result has been tested in the destination system. Browser processing protects against an upload by this calculator, but it does not make sensitive material appropriate to paste into an untrusted device or extension.

Limitations and safety boundary

It is not a quoted CSV parser, treats JavaScript characters rather than encoded bytes, and does not support multibyte byte widths, headers or nested delimiters. This is a preparation and review tool, not a standards-complete parser, security assessment, legal determination or production deployment system.

Source and verification

The transformation rule was checked against MDN Web Docs — TextEncoder on 2026-08-26. Recheck the destination specification when its grammar can change. All processing here runs in the current browser tab; ecech receives no input through a calculation API.