Use this tool to remove duplicate lines from any pasted text. It processes your input line-by-line and keeps only unique lines while preserving the original order. This is ideal for cleaning email lists, deduplicating URLs, removing repeated log entries, and cleaning exported data where the same item appears multiple times.
Order-preserving deduplication means the first time a line appears, it’s kept, and any repeated occurrences are removed. If duplicates still show up, it’s almost always because lines look the same but aren’t identical (extra spaces, different casing, or invisible characters). Use options like trim whitespace, normalize spaces, and case-insensitive dedupe to normalize input before filtering.
Remove Duplicate Lines Tool
Deduplicate text line-by-line with options for normalization and order handling.
Options
- Trim whitespace (left/right/both)
- Ignore empty lines
- Case-insensitive dedupe
- Normalize spaces (collapse multiple spaces/tabs)
- Keep first vs keep last occurrence
- Sort output (optional)
- Stats (unique count, removed duplicates count)
How to remove duplicate lines
- Paste your text (one item per line).
- Choose options (trim whitespace, ignore empty lines, case-insensitive).
- Click Remove Duplicates.
- Copy or download the unique list.
Examples
Deduplicate an email list
Dedupe log lines while keeping order
INFO boot WARN retry INFO boot ERROR fail
INFO boot WARN retry ERROR fail
Case-insensitive dedupe
Example.com example.com EXAMPLE.COM
Example.com
Troubleshooting
- Duplicates still appear: enable Trim whitespace, Normalize spaces, and Case-insensitive mode.
- Lines look identical but don’t match: hidden characters, different line endings, or tabs.
- Order changed: sorting mode is enabled (turn it off to preserve order).
Common questions
Does this tool preserve the original order?
Yes by default it keeps the first occurrence of each line and preserves the original order of those first occurrences.
Can I remove duplicates case-insensitively?
Yes. Enable Case-insensitive dedupe to treat Example.com and example.com as the same value.
Can I trim whitespace before deduplication?
Yes. Choose a Trim whitespace option (left/right/both) to normalize lines before deduplicating.
Can I ignore empty lines?
Yes. Enable Ignore empty lines so blanks are removed before processing.
Can I keep the last occurrence instead of the first?
Yes. Enable Keep last occurrence to keep the last instance of each unique line.
Can I sort the output alphabetically?
Yes. Enable Sort output (A → Z). Note: sorting changes the original order.
Can I remove duplicates from emails/URLs/domains/IPs?
Yes. This tool deduplicates line-by-line, so it works for any list where each item is on its own line.
Can I deduplicate very large lists?
It works best for typical copy/paste sizes. For extremely large inputs, consider splitting into chunks.
Will my text be uploaded to a server?
No. The deduplication runs in your browser; your text stays on your device.
How do I detect hidden characters?
Enable Trim and Normalize spaces. If duplicates still appear, the lines may contain tabs, different line endings, or invisible characters.