HIGH-PRECISION SPREADSHEET DIFF ENGINE
Built for analysts, accountants, and engineers who need to diff Excel files without uploading sensitive data to a server.
OUR STANCE ON PRIVACY
ExcelCompareColumns is a client-side spreadsheet comparison tool. All parsing, comparison, and rendering runs locally in your browser using Web Workers and SheetJS. No files ever leave your device, nothing is stored on a server, and no spreadsheet content is sent to third-party analytics.
WHY CLIENT-SIDE ONLY
- No file uploads — your spreadsheets never leave your browser.
- Works offline once the page has loaded.
- No third-party analytics on spreadsheet contents.
- You retain full ownership and control of your data.
CORE CAPABILITIES
- Visual file-to-file diff with synchronized side-by-side scrolling.
- Formula inspection — compare underlying formulas, not just displayed values.
- Smart fuzzy row alignment for sorted or shifted data.
- Column set operations: intersection, unique left, unique right.
- ID-based reconciliation for unordered ledgers and inventories.
- High-density printable HTML and CSV export.
HOW IT WORKS
Drop two files into File 1 and File 2. The engine parses every worksheet locally, aligns rows with a fuzzy signature algorithm, and highlights cell-level changes: added rows in emerald green, deletions in rose red, modifications in amber, and formula changes in indigo. Use Compare Columns for two-list set operations or Reconciliation for ID-based matching across unordered rows.