Line Counter
Count total, blank, unique and duplicate lines in any text, see the longest and average line length, and get a numbered copy of the whole thing.
How to use it
- Paste your lines — logs, lists, CSV rows, anything.
- Duplicate detection compares whole lines exactly, including whitespace.
- The numbered output is copyable, which is handy for referring to a specific line.
Examples
| A list with one repeated entry | Duplicates: 1 |
Paste text — a log file, a mailing list, a CSV export, anything organised one item per line — and this counts total lines, blank lines, and how many are exact duplicates of another line, alongside the longest and average line length. It is a fast way to sanity-check a file before feeding it into something else that will not forgive a stray duplicate or an unexpected blank row.
How duplicate detection works
Two lines count as duplicates only if they match exactly, character for character — including leading or trailing whitespace and letter case. A line with one extra trailing space is technically a different line from one without it, which occasionally explains a duplicate count that looks lower than expected when two entries look identical at a glance but are not byte-for-byte the same.
The numbered copy
The tool produces a numbered version of the full text, with each line prefixed by its line number, which can be copied out directly. That is useful when referring someone to “line 47” of a log file or a script, or when cross-checking a list against another tool that reports errors by line number.
Questions people ask
Why does my file show one more line than I expect?
A trailing newline at the end creates a final empty line. Tick the blank-line option to exclude it from the duplicate check.
Is anything uploaded or stored on a server?
No. Everything runs in your browser. Anything that persists is kept in this browser's local storage on your own device.
Last updated 22 August 2026