Remove duplicate lines from a list
Paste your list with one item per line to remove duplicate lines. The tool keeps the first occurrence of each line and removes the repeats, in the original order. You choose whether capitalization and accents matter and whether surrounding spaces are ignored. It shows how many duplicates it removed. Everything runs in your browser.
- ✅ Free
- 🔒 No sign-up
- 📱 Works on mobile
- ⚡ Instant results
🔒 Everything runs in your browser. Your data and files never leave your device.
📌 Key facts
- To remove duplicate lines, the tool compares each line with the ones before it and keeps the first occurrence.
- Your original order never changes.
- You choose whether capitalization, accents, surrounding spaces and blank lines count.
- The Duplicates only mode lists each repeated line once.
- Everything runs in your browser, so your list goes nowhere.
How duplicates are detected
The tool reads one entry per line and compares each line with the ones before it. The first occurrence stays, later ones are dropped, so your order is untouched.
| Option | Line 1 | Line 2 | Duplicate? |
|---|---|---|---|
| Ignore case (default) | Apple | apple | yes |
| Match case | Apple | apple | no |
| Ignore accents | café | cafe | yes |
| Ignore spaces (default) | "cat" | " cat " | yes |
\[ \text{duplicates removed} = \text{lines read} - \text{unique lines} \]
Common uses
- Email and contact lists: drop addresses entered twice before a mailing.
- SEO keywords: merge several exports without repeats.
- Names and codes: build a giveaway list or a guest list without accidental repeats.
- Logs and exports: spot recurring errors with the "Duplicates only" mode.
"Duplicates only" lists each repeated line once, so you see at a glance what was entered more than once.
How to remove duplicate lines step by step
To remove duplicate lines from a list, follow four steps. First, paste one entry per line in the top box. Next, tick the options that apply. Then read the result, which updates live. Finally, copy it or download it as a text file.
For example, a list of 500 addresses with 37 repeats gives 463 unique lines. The counter shows three values: lines read, unique lines and duplicates removed.
Pick the right options to remove duplicate lines
| Your list | Suggested options | Reason |
|---|---|---|
| Email addresses | ignore case, ignore spaces | Mary@mail.com and mary@mail.com reach the same inbox |
| Keywords with accents | ignore accents | cafe and café often overlap |
| Product codes | match case | AB12 and ab12 may differ |
| List copied from a spreadsheet | ignore blank lines | gaps do not count as entries |
So you tune how strict the comparison is for your data. If you hesitate, keep the defaults, then test with a small sample.
Common mistakes when you remove duplicate lines
- Forgetting spaces: "cat" and "cat " look identical but differ without the space option.
- Mixing two columns: because the tool compares whole lines, not separate cells.
- Expecting the order to change: but the first occurrence stays in place.
- Skipping a final read: for example, a typo creates a false unique entry.
Next, sort the lines to tidy the list. Also, the word counter checks the text length. Finally, the case converter makes capitalization uniform before you compare.
A worked example of how to remove duplicate lines
Here is a six-line list and the result for each mode. So you see exactly what the tool keeps.
| Input list | Unique lines mode | Duplicates only mode |
|---|---|---|
| apple | apple | apple |
| pear | pear | pear |
| Apple | banana | |
| banana | ||
| pear | ||
| pear |
With case ignored, Apple counts as a repeat of apple. As a result, the unique list keeps three lines and drops three lines. The Duplicates only mode shows apple and pear, because those are the two repeated entries.
Remove duplicate lines online or in a spreadsheet?
| Factor | This tool | Spreadsheet |
|---|---|---|
| Data | plain text, one entry per line | table with columns |
| Speed | live result | Data menu, then a confirmation |
| File to open | none | a workbook |
| Comparing several columns | no | yes |
In practice, the tool wins for a simple list copied from an email or a website. On the other hand, a spreadsheet stays useful when several columns must stay linked. If you want to remove duplicate lines before a giveaway, also try the random name picker.
Tips before you paste your list
- One entry per line: if your list uses commas, first swap the commas for line breaks.
- Run a short test: paste ten lines to check the options, then paste the rest.
- Keep the original: you copy the result, so your starting list stays intact in your own file.
- Count before and after: the counter shows lines read, unique lines and removed lines, so you can check quickly.
- Watch invisible characters: a trailing space or a non-breaking space can hide a match, so keep the space option on.
Also, if a list comes from several sources, merge them first. Then run the check once on the combined text, because that catches repeats across sources.
3 real-life examples
A grocery list
You paste "milk, eggs, milk, bread, eggs" with one item per line, 5 lines. The result has 3 lines (milk, eggs, bread) and reports 2 duplicates removed.
Uppercase and lowercase
With "Austin", "austin" and "AUSTIN", the default gives 1 line. Turn on Match case and all 3 stay.
Finding what repeats
On 200 email addresses, choose "Duplicates only": if 12 addresses appear more than once, you get a 12-line list showing which to clean up.