π Statistics & Probability
Remove Duplicates Tool
Remove duplicate lines, words, or values from any list. Free dedup tool with case-sensitivity options.
What This Calculator Tells You
This tool removes duplicate lines from a list and tells you exactly how many were removed. Use it to clean email lists, keyword lists, product SKUs, tags or any one-item-per-line data.
Choose whether 'Apple' and 'apple' count as the same item. The first occurrence of each item is kept, in its original order.
What to Enter
- List (one per line) β paste a column from a spreadsheet or any line-separated list.
- Case sensitive (yes/no) β 'yes' treats Email@site.com and email@site.com as different; 'no' treats them as duplicates. For email addresses, 'no' is usually what you want.
Worked Examples
1. A merged email list
Two sign-up exports combined into 1,240 lines.
- With case sensitivity off, the result might read 1,240 original, 1,105 unique, 135 removed, with the clean list ready to copy.
2. Keyword research
Keyword ideas collected from three tools overlap heavily.
- Removing duplicates shows how many unique keywords you actually have before grouping them.
3. Product tags
A list where 'Summer' and 'summer' both appear.
- Case-insensitive mode keeps the first spelling and drops the other.
How to Read Your Result
- Removed = original β unique.
- A high share of duplicates in a merged list means your sources overlap more than expected.
- Leading and trailing spaces can make otherwise identical lines look different β run the text cleaner first if counts look off.
Common Mistakes to Avoid
- Pasting multi-column rows β the whole line is compared, not one column.
- Stray spaces that stop duplicates matching.
- Using case-sensitive mode for emails, which leaves duplicates in.
When to Use This Calculator
- De-duplicate email and contact lists before importing.
- Clean keyword, URL or SKU lists.
- Count unique values in a column quickly.
- Prepare tag and category lists.
Frequently Asked Questions
Which copy is kept?
The first occurrence of each item, in the original order.
Is my data uploaded?
No. The list is processed in your browser.
Can I remove duplicate rows from a CSV?
Yes, if whole rows are identical. To de-duplicate by one column, use your spreadsheet's remove-duplicates feature on that column.
How many lines can I paste?
Tens of thousands of lines work in most modern browsers.
Do you store the values I enter?
No. All calculations happen in your browser. Your data never leaves your device.
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