Compare Excel files on a Mac by their records

When two workbooks come from different systems, matching cell positions is often the wrong comparison. One sheet may be sorted by customer and another by date. A useful comparison first identifies the same record, then compares the fields that mean the same thing.

Spreadsheet Comparison imports a selected worksheet from an XLS or XLSX file on macOS 14 or later. You can compare that sheet with another workbook sheet or a CSV export. Input files are processed locally on your Mac.

Select the sheet that contains the records

Start by checking the workbook in the application that produced it. Find the tab containing the actual export, not a summary chart, pivot output or cover sheet. Confirm that its header row describes the data below it. A worksheet arranged as a presentation with several tables and decorative titles may need a clean export before it makes a useful comparison table.

In Spreadsheet Comparison, choose each workbook and select the worksheet to load. Each side contributes one selected sheet. This is not a workbook-wide comparison of every tab, chart, style, macro or formula definition.

Check the workbook and worksheet limits

Excel import has technical limits that remain after purchase: a 64 MB workbook, and a selected worksheet range of at most 250,000 rows, 10,000 columns and 5 million cells. The cell limit applies to the declared rectangular range, including empty cells inside it. These are Excel import limits, not CSV row limits.

Cached Excel formula results are read from the saved workbook and are not recalculated. Recalculate and save in the source spreadsheet application when current formula results matter.

These limits protect the workbook import process and are separate from the free trial. A mostly empty sheet can still have a large declared range if data or formatting extends to a distant row or column. Make a clean data-only working sheet or export the required records as CSV if a workbook exceeds the limits; preserve the original.

Decide what identifies a row

Suppose a synthetic inventory workbook contains warehouse, sku and quantity. If a SKU appears in more than one warehouse, use warehouse and SKU together as the key. Choosing only SKU can group unrelated stock locations into the same comparison.

Map equivalent fields across the selected sheets. “Item Code” may correspond to “SKU”; “Available” may mean a different quantity from “On Hand.” Check the definitions before accepting a suggestion. A matching header is evidence about naming, not proof about business meaning.

Understand saved formulas

The app reads cached Excel formula results; it does not recalculate formulas. A formula cell can therefore reflect the last result saved by the program that wrote the workbook. If formulas depend on recently edited cells or external sources, open the workbook in the appropriate spreadsheet application, recalculate and save it before importing. Missing or unsupported saved values should be resolved in that source application.

For example, a workbook might contain a formula for quantity × unit_price. The comparison can inspect its saved result as imported data. It does not prove that the formula expression itself is equivalent to the expression in a second workbook, and it cannot refresh an external data connection.

Protect identifiers and inspect formatting

Excel can remove leading zeros and convert long numeric-looking values when importing or entering data. Microsoft recommends treating identifiers as text when their exact digits must be preserved. See Microsoft’s guidance on leading zeros and large numbers.

Compare a known identifier after import, especially postal codes, part numbers and long reference numbers. The workbook reader uses available formatted display strings. It cannot restore digits that were already lost in the source file. Also inspect a date, a decimal and a blank cell: the same underlying value can be represented differently by two exporters.

Interpret the output as a data review

After comparing, review changes and records found only on one side. A row absent from a weekly sheet may have been excluded by a filter or moved to a different tab. Use the full row preview and original filenames to retain context. Export the result only after spot-checking records you already understand.

Encrypted or unsupported workbooks may require a supported, unencrypted export. Save a separate working copy if you need to reshape a sheet. A plain CSV export is also useful when you want to inspect exactly which text values will be compared.

For the next step, read how to choose a comparison key. The same identity rule applies whether the original records came from CSV, XLS or XLSX.