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Skip to contentPrefix every line with a line number.
Prefix every line with a line number.
Text tools help you clean, transform, and analyse strings without opening a heavy editor. Everything happens in a single page with instant feedback.
Use this free Add Line Numbers whenever you need a reliable result without creating an account or installing software. It loads in one click and works on desktop and mobile browsers.
Tentaco runs this tool in your browser whenever possible. Text and structured input you paste are handled in the page session unless the tool explicitly fetches remote data. Close the tab or clear the page after use on shared computers. Features that call external APIs (such as URL fetchers) only send the data required for that request.
Prefix every line with a line number. Open the tool in your browser — no account or install required.
Yes — runs in browser.
No — processing runs locally in your browser. Your files and inputs do not leave your device unless the tool explicitly uses the network.