How to use the Line Numberer
Last verified 2026-08-09 · about 5 minutes to read
The short version
- 1.Paste your lines. Any line ending works — CRLF, LF or CR.
- 2.Set the numbering. Zero-padding keeps the text aligned once you pass line 9, which is what makes a numbered list readable in a monospace font.
- 3.Or strip numbers instead. Switch to remove mode to clean up text copied out of a code sample, a log viewer or a PDF.
Why this is worth getting right
Every competitor adds line numbers. Almost none remove them, which is the direction people actually need more often — you copy a snippet out of a documentation page or a log viewer and the numbers come with it. This tool does both, and its stripper recognises six separator styles rather than assuming one.
Method 1 — use the Line Numberer on this site
The fastest route. It runs entirely in your browser, so nothing is uploaded and there is no queue to wait in. No account is needed and there is no daily limit.
- Paste your lines. Any line ending works — CRLF, LF or CR.
- Set the numbering. Zero-padding keeps the text aligned once you pass line 9, which is what makes a numbered list readable in a monospace font.
- Or strip numbers instead. Switch to remove mode to clean up text copied out of a code sample, a log viewer or a PDF.
Method 2 — do it without this site
Worth knowing, because a tool you cannot replace is a dependency rather than a convenience. Most tasks in the text division have a command-line or built-in equivalent; it is usually more setup and less convenient, but it works offline and it is scriptable, which matters once you are doing something a hundred times instead of once.
What this tool will not do
Every tool has an edge. These are ours for line numberer, stated up front so you find out here rather than halfway through a deadline:
- Removal is pattern-based, so a line genuinely starting with a number and a separator will lose it. The changed-line count makes that visible.
- Numbers are added as literal text, not as a gutter — pasting the result back into an editor includes them.
Questions people ask
How do I remove line numbers from copied code?
Switch the mode to "remove existing line numbers". It strips a leading number followed by a common separator — a dot, colon, bracket, pipe, tab or two-plus spaces — and leaves the rest of the line untouched, including its indentation.
Why would I zero-pad the numbers?
Without padding, line 9 and line 10 start at different columns and the text jumps left and right. Padding to a fixed width keeps everything aligned, which matters as soon as you have more than nine lines in a monospace font.
Can I start from zero, or count in steps?
Yes. Start at any number including zero or a negative, and step by any amount — step 10 gives 10, 20, 30 for BASIC-style listings or test case IDs.
What happens to blank lines?
By default they stay blank and are not counted, so the numbering follows the content rather than the whitespace. Turn the option off if you want every physical line numbered including the empty ones.
Will removing numbers damage lines that start with a real number?
It can. A line like "2024 was a good year" begins with a number followed by a space, which matches the pattern. Check the result — the tool reports how many lines it changed so a surprising count is visible immediately.