CSV Tools New Tool

Free Online CSV Duplicate Remover, By Row or By Column

Remove duplicate rows from a CSV in your browser. Judge duplicates on the whole row or on the columns that identify a record, such as an email, and keep the first copy, the last one, or whichever copy has the most fields filled in. You can also list the duplicates instead of removing them, or add a count column.

Free Forever Nothing Uploaded Key columns Many files at once

Free Online CSV Duplicate Remover, By Row or By Column

Advertisement Slot (Top Banner) Google AdSense Unit • Responsive Banner

Bulk CSV Duplicate Remover Your file is read inside this tab. Nothing is uploaded anywhere.

Drop the CSV files you want deduplicated Each file is handled on its own. Rows are never merged between files. Choose files Up to 25 MB per file. Nothing is uploaded.

Or paste it

Reading the file Separator First row is a header Trim spaces around values

Two rows are the same when

What to do Copy to keep

Matching Ignore capitals Ignore spaces at the ends of values Treat rows with an empty key as duplicates of each other

Writing the result Separator Quote every field Windows line endings, for Excel Add a byte order mark, so Excel reads accents

0 files 0 rows in 0 rows out 0 values repeated

All the rows

Nothing to show yet.

Result

Nothing to show yet.

Buy Us A Coffee

Enjoying WizTools123? Help keep our server infrastructure 100% free and open for everyone.

Buy Us A Coffee

Sponsored Content (Below Tool) Google AdSense Placement

How to Remove Duplicate Rows From a CSV

A few steps, and nothing is uploaded.

Drop the files in One or many. Each file is deduplicated on its own; rows are never merged between files.

Say what makes two rows the same Every column, or just the ones that identify a record. An email column alone is usually the right answer for a contact list.

Choose which copy survives First, last, or the one with the most fields filled in. The last of those is usually what you want when the duplicate was a later, better record.

Download, or switch to a report The mode menu can list only the repeated rows instead of removing anything, which is how you check before you commit.

What to Know About Removing Duplicates

Which copy survives, and why that choice matters.

Judging on the whole row finds almost nothing useful. Real duplicates are rarely identical: the same customer appears twice with a different phone number, or a later signup date. That is why the key column choice exists, and why it is the option worth setting.

Keeping the most complete copy is usually the right answer. When the same email appears three times, the useful record is normally the one where the most fields are filled in, not the one that happened to come first. That option counts non empty values across the row and keeps the winner, with the earliest row winning a tie.

Ignoring capitals matters more than it sounds for email. Addresses are routinely stored with inconsistent capitals, and "BO@example.com" and "bo@example.com" reach the same mailbox. With capitals ignored those are one person; without, they are two. The value itself is never changed, only the comparison.

Rows with an empty key are kept apart by default. Three rows with no email are three unknown people, not one person recorded three times, so they are left alone. The switch exists because in some files an empty key really does mean one bad record repeated.

The count column answers a different question. It keeps one copy of each row and adds how many times that row appeared, which turns a duplicate problem into a frequency table. Useful for finding out which value is repeated most, rather than just removing the repeats.

Each file is handled separately, always. Dropping in twelve exports does not look for duplicates across them. Combining files is a different operation, and doing it silently inside a deduplicator would be a surprising way to lose data.

Key Features & Capabilities

What this tool does, and what it deliberately does not.

Key columns Judge duplicates on an email, an ID, or any combination of columns, named by heading or letter.

Most complete copy Keep the copy with the most fields filled in, which is usually the record worth keeping.

Count column Add how many times each row appeared, turning the duplicates into a frequency table.

Report mode List only the repeated rows, or only the unique ones, without changing anything.

A folder at a time Every file deduplicated with the same rules, downloaded together as one zip.

Nothing is uploaded Contact lists are deduplicated inside this tab and never sent anywhere.

About the CSV Duplicate Remover

Duplicate rows arrive in two shapes. The easy shape is an exact repeat, usually caused by running an export twice or pasting the same block twice, and almost anything can remove those. The hard shape is the one that matters: the same person or product recorded more than once with slightly different details, which is what happens whenever data is entered by hand or merged from two systems.

The hard shape cannot be found by comparing whole rows, because the rows genuinely differ. It is found by deciding which columns identify a record, which only you know. An email identifies a contact; a name does not, because two people share a name. An order number identifies an order; a date does not. Once the key is chosen, the duplicates are obvious.

Then comes the question most tools skip: which copy survives. Keeping the first is the usual default and often wrong, because the later record is frequently the corrected one. Keeping the last is wrong just as often. Keeping the copy with the most fields filled in is the answer that matches what people actually want, since the duplicate that carries a phone number is more useful than the one that does not, whenever it arrived.

Frequently Asked Questions

Key columns, which copy is kept, counts and reports.

Set "two rows are the same when" to the columns you name, and type Email. Rows sharing an email are then treated as the same record even though the other columns differ.

Whichever you choose: the first, the last, or the one with the most fields filled in. That last option counts the non empty values in each copy and keeps the fullest, with the earliest row winning a tie.

With "ignore capitals" on, yes, which is right for email since both reach the same mailbox. The value you keep is never rewritten, so whichever row survives keeps its original spelling.

By default they are all kept, because three rows with no email are three unknown people rather than one person recorded three times. The switch lets you treat them as duplicates of each other instead.

Yes. The mode menu has an option to show only the repeated rows, and another to show only the rows that appear exactly once. Nothing is removed in either case.

No. Each file is handled on its own. Merging files is a separate operation and doing it quietly inside a deduplicator would be an easy way to lose track of where a row came from.