Line Numbering
Number plain-text records with exact start and step values, blank-line policies, padding and full UTF-8 exports.
Your inputs stay in your browser.Maximum 2 MiB source, 100,000 lines and 5 MiB output. Start ±10^18; step 1-10^9; digit width 1-30. Separator is literal text (up to 30 code points). This is plain text, not a CSV parser. Drafts stay in memory only; refreshing clears them. Processing and exports stay local.
Enter values or try an example, then choose Calculate / Generate.
How to use Line Numbering
Paste plain text or import a UTF-8 .txt file. Set start, step, minimum width and literal separator. Choose before/after placement, a blank-line policy and optional first-line header. Generate and download all numbered text; import and clearing can be undone.
Worked example
alpha and beta with start 1 and separator '. ' become '1. alpha' and '2. beta'. Start -3 with width 3 yields -003. Preserved blank lines consume no number.
Rules and limits
2 MiB source, 100,000 physical lines and 5 MiB output. Start within ±10^18; step 1-10^9; digit width 1-30. Separators have at most 30 code points and no line breaks. CRLF, CR and LF become LF; a final terminator is preserved without inventing an extra record. This is not a structural CSV or Markdown parser. Preview up to 1000 lines, complete exports.
What should we improve next?
Help shape the next update to Line numbering. Tell us what would make it better for you.
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