Free CSV Cleaner
Clean messy CSV and Excel files instantly — remove empty and duplicate rows, standardize phones, dates and names, flag bad emails, and download a report of every change.
Want to review each change before accepting it, with undo and an Excel export? Try the new guided workspace.
How to Clean a CSV File Online
Messy CSV files are one of the biggest time-wasters for sales teams, recruiters, and marketers. Exported contact lists often contain empty rows, inconsistent spacing, duplicate entries, and formatting errors that break imports into your CRM or email tool.
Our free CSV Cleaner fixes these issues in seconds. Paste your data or upload a CSV or Excel (.xlsx) file, choose your cleaning options, and click clean. The tool runs entirely in your browser — your data is never uploaded to a server, making it completely private and secure.
Common use cases: cleaning exported lead lists before a cold email campaign, preparing contact data for CRM import, standardizing spreadsheet exports, and removing junk rows from scraped data. Because everything happens locally, you can clean sensitive customer data without privacy concerns.
Learning to do this for clients? The Freelance Hub has step-by-step guides and practice projects.
What each option does: Merge duplicate emails removes a repeated address only when that row adds nothing new; rows that share an email but differ elsewhere are both kept and listed for you to decide. Flag invalid emails adds an email_check column marking bad formats and likely domain typos such as gmial.com. Standardize phones converts US and Canadian numbers to +1XXXXXXXXXX and keeps international numbers that start with + or 00. Standardize dates rewrites recognizable dates as YYYY-MM-DD. When 03/04/2026 could mean March 4 or 3 April, the dates are left unchanged until you choose how to read them, and two-digit years are left alone unless you switch on Expand 2-digit years. Trim whitespace removes spaces at the start and end of a cell only; Collapse extra spaces & line breaks also tidies the inside of a cell. Neutralize formulas puts an apostrophe in front of cells that start with = or @ so a spreadsheet will not run them. Fix name capitalization only touches names typed in all capitals or all lowercase. Split full name adds first_name and last_name columns next to the original.
The cleaning report: every run produces a summary of rows removed and cells changed, a list of rows that need a human look (unrecognized phones or dates, invalid emails, rows with too many cells), and a downloadable change log with the before and after value of every edit. Anything the tool cannot settle is left unchanged and listed. If other dates in a column show which comes first, day or month, the column is read that way and the affected dates are listed for you to check.
Embed This CSV Cleaner on Your Site
This CSV cleaner is free to embed on any website or blog — paste the snippet below where you want the tool to appear, and your visitors can clean CSV data right on your page. The only condition is that the built-in “Powered by SmartDataAI” attribution link stays in place; it is part of the widget and keeps the tool free for everyone. The widget is the paste-data version of this tool: it runs entirely in the visitor’s browser, and no data is uploaded anywhere.