Free CSV tools that run entirely in your browser

Split, merge, remove duplicate rows, and convert CSV files in seconds. No signup, no installation, and your files never leave your device.

100% Free No Signup No File Upload Handles Large Files Works Offline
Split a CSV file now →

Core CSV Utilities

CSV Splitter

Split large CSV files by number of rows, file size, or column value. Keeps headers in every part.

CSV Merger

Combine multiple CSV files into one, even when their columns don't match exactly.

Duplicate Remover

Delete duplicate rows from a CSV — across all columns or only the columns you choose.

Large CSV Viewer

Open and view massive CSV files (up to gigabytes) in your browser. Fast search and client-side paging.

Delimiter Changer

Convert separator commas to semicolons, tabs (TSV), pipes, or custom characters instantly.

Column Extractor

Select and extract specific columns from your CSV files to create clean, simplified subsets.

Data Format Converters

CSV ⇄ JSON

Convert CSV data to a pretty-printed JSON array of objects, or JSON back to standard CSV.

CSV → XML

Convert comma-separated values to structured XML markup with tag names matching headers.

CSV → YAML

Format spreadsheet rows into clean, indented YAML properties for DevOps configurations.

CSV → Markdown

Generate clean GitHub-flavored markdown tables for documentation, AI prompts, and wikis.

CSV → HTML

Transform tabular rows into standard semantic HTML tag code for website embeds.

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Enterprise Privacy

The Ultimate Privacy-First Online CSV Toolbox

Local Processing: Your Data Stays 100% Private

In today's data-driven world, Comma-Separated Values (CSV) files are the universal language of databases, spreadsheets, CRMs, and email marketing software. Whether you are managing customer directories, importing sales reports, or cleaning database tables, you constantly need to split, merge, convert, or clean up CSV data. However, most online utility websites force you to upload your sensitive spreadsheets to their remote servers, which raises massive data protection issues and exposes you to potential leaks.

CSV Toolbox solves this mismatch by offering a suite of professional-grade, web-based CSV utilities that run entirely inside your browser. By leveraging advanced HTML5 FileReader APIs and client-side JavaScript streaming (using Web Workers), we process files of any size locally on your device. Your data never leaves your computer, making it 100% secure and fully compliant with strict data policies like GDPR and HIPAA.

Local Streams: Speed Meets Privacy

Uploading files to online servers is slow, especially when dealing with large datasets of hundreds of megabytes. CSV Toolbox removes the upload step completely.

Because the data is read directly from your local hard drive into your browser's execution memory, files are processed instantly. A 500MB CSV file can be split, merged, or converted in seconds—ten times faster than server-side conversion sites. Once you load our pages, the tools can even function offline, giving you a reliable desktop-like utility wherever you are.

Core CSV Utilities

Our toolkit contains everything you need to manage spreadsheet files without opening heavy applications like Microsoft Excel or Google Sheets (which often slow down or truncate rows beyond the 1.04 million limit):

  • Splitter: Divide large CSVs by rows, size, or unique values.
  • Merger: Combine multiple spreadsheets into one with aligned columns.
  • Deduplicator: Delete duplicate rows across selected columns dynamically.
  • Large Viewer: Read gigabytes-large files with fast pagination and search.
  • Delimiter Changer: Convert separators (commas, semicolons, tabs) instantly.
  • Extractor: Filter and export specific columns.

Format Converters for Developers

Need to integrate tabular data into code or documentation? CSV Toolbox features one-click format converters:

  • CSV to JSON: Convert spreadsheet rows to standard JSON objects.
  • CSV to XML: Map your rows to structured XML tags.
  • CSV to YAML: Generate clean configurations.
  • CSV to Markdown: Export clean markdown tables for wikis or AI prompts.
  • CSV to HTML: Output HTML table codes for fast web embeds.

100% Free & Open Source

CSV Toolbox is 100% free with no signups, no paywalls, and no usage limits. Our processing is open-source, allowing developers to inspect exactly how their files are handled.

Start splitting, converting, and cleaning your CSVs safely today with absolute peace of mind.

Q&A

Frequently Asked Questions

Are these CSV tools really free?

Yes. Every tool is completely free with no signup, no usage limits and no premium tier. The site is supported by unobtrusive ads.

Is my data uploaded to a server?

No. All processing happens inside your browser using JavaScript. Your files are never transmitted anywhere, which also makes the tools fast and safe for sensitive data.

How large a CSV file can I process?

Files are processed as a stream, so hundreds of megabytes work fine on a typical laptop. The practical limit depends on your device's memory.

Do the tools work on Excel exports?

Yes. Any standard CSV works, including files exported from Excel, Google Sheets, databases and CRMs. Delimiters and quoting are detected automatically.