ConvertCSV

Browser-based CSV transform

Diff CSV

Compare two CSV files and list added, removed, and shared rows. Everything runs locally in your browser — paste CSV, set options, preview, then copy or download.

Left / primary CSV

Paste CSV or upload a file

Second CSV

Second CSV (compare against)

Options

Configure how this transform runs

No extra options — run the transform on your CSV input.

Output Preview

Transformed CSV

Run the transform to preview CSV output here.

Diff CSV

Diff CSV compares two tables on shared columns and labels each row both, only_left, or only_right in a _diff column.

Conversion runs entirely in your browser. CSV contents are not uploaded to a server for this transform.

Key features

  • Client-side parsing and transform
  • Copy or download CSV output
  • Works with paste or file upload

About the two CSV files to CSV with _diff status format

Row equality is based on shared column values joined with an internal separator — duplicate identical rows collapse to one key.

Common use cases

  • Change detection between exports
  • QA of cleaned files

How to use this tool

  1. Paste or upload CSV (and a second file when the tool needs it).
  2. Set options if shown, then click Transform.
  3. Copy or download the result.

Tips for best results

  • Ensure both files share the columns that define sameness.
  • Preview before download and keep a copy of the original file.

Common pitfalls

Quoted commas and newlines must stay valid CSV — paste intact exports when possible.

Frequently asked questions

Is my CSV uploaded?

No. Transforms run locally in the browser tab.

For more background on data formats and conversion workflows, read our format guides or browse the converter blog for step-by-step walkthroughs linked to each tool.