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.

Why CSV Toolbox?

Most online CSV tools upload your data to a server, limit file sizes, or hide features behind a signup wall. CSV Toolbox is different: every tool runs locally in your browser using streaming processing, so it stays fast even with files of hundreds of megabytes, and your data stays private. Once a page is loaded, the tools even work offline.

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.