Add Line Numbers
Prefix each line with sequential numbers.
How to use
- 选择「添加行号」或「删除行号」，结果实时自动处理。
- 可设置起始数字、递增步长、编号位数（前导零）、前缀、后缀和分隔符。
- 「空行参与编号」关闭时，空行不占编号，适合给内容行连续编号。
- 「删除行号」会移除行首形如「数字+分隔符」的编号，不影响行内数字。
SSS
Does Add Line Numbers upload my data?
No. Processing stays in your browser and is not uploaded.
Do I need an account?
No. Open and use — no signup.
How is this different from upload-based tools?
Tools run locally in your browser; content is not sent to our servers for processing.
Are there limits?
Limited by device memory and the browser; very large inputs may slow the page.