Compare Two Excel or CSV Files

About the Compare Two Excel or CSV Files

Compare an original and a changed version of a sheet — two Excel workbooks, two CSV files, an Excel file and a CSV export of it, or two sheets of one workbook. Rows are matched either by key columns (an order number, SKU, employee code or e-mail, wherever the row is) or by position, where inserted and deleted rows are detected so one new row does not make every following row look changed.

The result lists added, removed and changed rows, with each changed cell shown as “old → new”. You can ignore letter case, extra spaces and number formatting (so 1,000, 1000.00 and ₹1,000 count as equal), match columns by header name so column order does not matter, and download a colour-coded XLSX report or a CSV change log. Both files are read on your device.

Common uses

• Seeing what changed between this month’s and last month’s price list, stock report or payroll sheet.
• Checking an edited copy of a spreadsheet before replacing the original.
• Reconciling an export from one system with the data in another (bank vs ledger, CRM vs billing).
• Verifying that a CSV export contains exactly what the workbook does.

How rows and cells are matched

• Key columns: rows with the same values in the chosen columns are compared, wherever they are; rows whose key exists on one side only are added or removed. Repeated keys are matched in order and reported. A column named like an ID whose values are unique is suggested.
• Row position: the two sheets are aligned like a text diff (Myers’ algorithm), so inserted and deleted rows are found; a removed and an added row that share at least half their values are shown as one changed row.
• Columns are matched by header name (order does not matter; columns that exist on one side only are listed), or by position. Columns with neither a header nor any value are ignored, and if the two sheets have no column in common you are asked to check the header rows rather than shown a meaningless result.

Excel cells are compared by their stored values, and also count as equal to the text Excel displays — so an XLSX and a CSV export of it (with formatted or raw values, and dates such as 28/09/2026 or 2026-09-28) compare as equal.

What “ignore number formatting” does

With it on, numbers written differently are equal: 1,000 = 1000 = 1000.00, ₹1,499 = 1499, 12.5% = 0.125, (1,250.00) = -1250. Codes with leading zeros are never treated as numbers, so 007 and 7 stay different. Turn it off to see formatting changes as differences.

The report

The XLSX report has three sheets: a summary of the comparison and its options; the differences, with added rows in green, removed rows in red and changed cells in amber plus a “Changes” column that lists every “old → new”; and a change log. The CSV change log has one line per changed cell, and one line per filled cell of each added or removed row (change, key, row_original, row_changed, column, old_value, new_value).

Limitations

• Files up to 50 MB (workbooks) or 100 MB (CSV) each, and about 3 million cells per file. Very different large sheets are aligned one-to-one after a short time limit, with a note.
• Cell values are compared, not formatting, comments or formulas (a formula compares by its saved result).
• Rows are matched one-to-one; a row that was split into two, or two rows merged into one, shows as removed and added.
• Dates are equal when they are the same day and time; time zones are not considered.

Privacy

Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.