GENERAL
Is ExcelCompareColumns free to use?
Yes. ExcelCompareColumns is a browser-based spreadsheet comparison tool available at no cost. All features run locally in your browser with no account required.
Does ExcelCompareColumns upload my files to a server?
No. All parsing, comparison, and rendering runs 100% locally in your browser using Web Workers and SheetJS. Your spreadsheets never leave your device, and the tool works offline once loaded.
What file formats are supported?
ExcelCompareColumns supports Excel workbooks (.xlsx) and comma-separated values (.csv). You can load two files at a time for side-by-side visual diffing.
Do I need to create an account?
No account is required. Open the site, drop in your files, and start comparing immediately.
COMPARISON MODES
How do I compare two Excel sheets?
Use File Comparison mode. Drop both files into File 1 and File 2. The engine parses all worksheets locally and presents a side-by-side view with synchronized scrolling. Modified cells render in soft amber, added rows in emerald green, deleted rows in rose red, and formula changes in deep indigo.
How do I compare two columns in Excel?
Use the Compare Columns tool. Select the column from File 1 and File 2, then run the comparison. The engine computes set intersection, unique left values, and unique right values, with instant CSV download of matching and non-matching rows.
How do I compare two lists in Excel?
Use Compare Columns mode for list-based comparison. Pick the column from each file containing your lists (e.g. email subscriber lists, part numbers, or product SKUs). The tool computes intersection, unique left values, and unique right values instantly.
How do I compare two Excel sheets for differences and matches?
Use File Comparison mode. Drop both sheets into File 1 and File 2. The comparison engine highlights cell-level differences and matches side-by-side. Click “Export Diff” to generate a high-density, printable HTML report summarizing all differences and matches.
How can I match two columns and output a third column?
Use Reconciliation Mode. Pick the Primary Key column (e.g. Account Code or SKU) from both files and the Value column to compare. Records are matched by key ID across both sheets. Export the reconciled result as CSV to output matched values into a third column.
How do I compare two sets of data?
Choose the comparison mode that fits your data: File Comparison for full sheet diffs, Compare Columns for two-list set operations, or Reconciliation for ID-based matching across unordered rows. All processing happens locally in your browser — no files are uploaded to a server.
TECHNICAL
Does ExcelCompareColumns inspect formulas or only displayed values?
ExcelCompareColumns inspects underlying formulas (e.g. `=SUM(A1:A100)` vs `=SUM(A1:A99)`), highlighting subtle calculation errors before they reach production. Standard tools often only read calculated display numbers.
What happens if a row is added or sorted differently?
Conventional diff tools mark all subsequent rows as deleted/added. ExcelCompareColumns uses smart fuzzy row alignment to compute row signatures and keep matching data aligned seamlessly.
Can I export the comparison results?
Yes. Click “Export Diff” in the toolbar to generate a high-density, printable HTML report suitable for PDF conversion. Column and reconciliation results can be downloaded as CSV.
Does it work offline?
Yes. Once the page has loaded, you can disconnect your internet entirely and continue diffing files offline.
NEED MORE HELP?
Start a new comparison at ExcelCompareColumns — all processing runs locally in your browser.