Line Numberer
Add sequential line numbers to text with a custom start number, separator and zero-padding, and skip blank lines without consuming a number.
1. Buy milk 2. Walk the dog 3. Reply to emails 4. Pay the billsResult: 4 lines, 63 characters
A number in front of every line
Line Numberer prefixes every line of your text with a running number. You choose where the count starts, which separator sits between the number and the line (a period, colon, tab, space, or none at all), and whether numbers are zero-padded so they line up in a neat column. Turn on Skip blank lines and empty lines are left unnumbered without consuming a number, the way nl and cat -b do. The numbered result updates live as you type and can be copied with one click.
When it is handy
Use it to number steps in an instruction list, label rows before pasting into a document, prepare ordered references, or make log lines easier to cite. Zero-padding keeps two- and three-digit numbers aligned, which is useful when the output goes into a fixed-width or monospaced context.
Frequently asked questions
Can I start numbering from something other than 1?
Yes. Set any start number and each following line increments by one. You can begin at 0, 100, or any whole number you like.
What does zero-pad to align width do?
It pads shorter numbers with leading zeros so every number is the same width. For example, across ten lines you get 01 through 10 instead of 1 through 10, keeping the text aligned.
Can I put text around the number, or the number at the end of the line?
Yes. There are fields for text before and after the number, a separator that can be nothing at all, and a choice to put the number at the start or the end of each line.
Can I pad to a fixed number of digits, or delete the blank lines?
Yes. Turn on Zero-pad to align width and a Digits field appears. Left blank, the numbers get as many digits as the largest one needs; type a width and each number is padded to at least that many, so the column keeps the width you chose however short the list. A number that needs more digits still gets them, and a width past the limit is refused with a note naming it. Remove blank lines deletes empty and whitespace-only lines before numbering, so they leave no gap in the output, while Skip blank lines keeps them in place, unnumbered.
Can I number a whole file and save it, and does a final line break get a number?
Yes. Open file… reads a text file into the box, and Download saves the result under that file’s name with -numbered added — notes.txt comes back as notes-numbered.txt. A file that ends in a line break is numbered by its lines, as nl and cat -n do, so no number is left on an empty last line, and in a file with Windows line endings a number put at the end of the line stays on that line.