Free online line number tool. Add line numbers to text with custom start number, step, separator, and alignment. Great for code display, document formatting, teaching materials. Client-side processing, no data uploaded. · Client-side processing · Your data never leaves your device
Zero dependencies·Works offlineThe Line Number Tool is a free online text processing tool that adds line numbers to each line of text. It supports custom start number, step, separator, alignment, and other parameters to meet various line number format needs. Commonly used for code display, document formatting, teaching materials, log analysis, and more. This tool runs entirely in your browser and never uploads any text data to servers.
Step 1: Enter text. Paste or type the text that needs line numbers in the input box. It can be code, documents, lists, or any text content. The line count and character count are displayed in real-time below the input box.
Step 2: Set parameters. Adjust line number parameters as needed: start number (default 1), step (default 1, set to 5 for 5,10,15...), separator (characters between line number and content), alignment (right alignment is neater), whether to skip empty lines, whether to zero-pad, etc.
Step 3: Add line numbers. Click the "🔢 Add Line Numbers" button and the result appears in the output area. You can copy the result or click "↩ Remove Numbers" to restore the original text.
Code display: Add line numbers when showing code in blogs or docs for easy referenceTeaching materials: Provide students with numbered code or text for classroom discussionDocument formatting: Add line numbers to contracts, regulations for easy citationLog analysis: Number log files to quickly locate issuesPoetry formatting: Number poetry lines for citation and analysisA: Supports custom start number (default 1), step (default 1), separator (dot, colon, pipe, space, etc.), alignment (left/right), and zero-padding. Meets various line number format needs.
A: Yes. Check the "Skip empty lines" option and empty lines won't be numbered. Non-empty lines are numbered sequentially. This is especially useful when processing code.
A: Completely safe. This tool is a pure front-end implementation. All processing is performed locally in your browser. Text content is never uploaded to any server. All data is cleared when you close the page.
A: Right alignment lines up all line numbers at the ones digit, which looks neater for many lines (100+). Left alignment starts from the left side, suitable for fewer lines. Zero-padding adds leading zeros to make all line numbers equal width.
🔒 No data uploaded to servers. This tool runs entirely in your browser. All text processing is performed on your device. Your text content is never sent to any server over the network. Data is cleared when you close the page. Use with confidence.