A little guidance goes a long way.

Try the sample, or open the workspace and choose two files. Each file can be Excel XLSX or CSV. Confirm the header previews, connect matching columns, review the rules, then compare.

Choose fields that together identify one record. Order 123 can contain several products: use Order number and Item number together. Do not use Quantity or Price as identifiers when those are the differences you want to find. Duplicate identifiers are flagged rather than silently paired.

Connect columns with the same meaning, such as Quantity and Order_Qty. Review suggested types; keep identifiers as text if leading zeros matter. Scroll across the mapping table to see every control.

It is an absolute difference, not a percentage. A price difference of 0.01 passes when your allowed difference is 0.01. Date differences are calendar days. Each cleanup option can be turned off when it changes the meaning of an identifier.

Filter by category, search for an identifier, and select Inspect to see both original values and the reason. Scroll across wide tables on small screens. Download exceptions includes only the current filter and search results, in an Excel file.

Name and save a setup in Reuse a comparison setup. If asked to reconnect, select Open secure sign-in. Finish in that new tab, return to the original comparison tab and select Continue. Your files remain in the original tab. Next time, choose your files, connect your account and select a saved setup. Review any columns that need remapping.

Source files and results are held only in the comparison tab's memory. Reloading or closing it discards them. Download a setup or save it to your account to keep the rules; choose the source files again next time. Help and account links open separately to keep the comparison available.

Use UTF-8 comma-separated CSV or XLSX with unique, nonblank column names. XLSX reads stored values and cached formula results; it does not recalculate formulas. The workbook must use Excel's 1900 date system. Text dates must use YYYY-MM-DD or MM/DD/YYYY. Keep long identifiers and leading zeros as text in Excel. CSV source row numbers identify the physical line where a record starts, including when a quoted value spans lines.

After the app loads, turn your browser offline and compare, inspect and export. Those operations work locally. Account connections and saving or retrieving setups need the internet. See Privacy and data handling.