CSV & Excel Diff
Compare two CSV or Excel files row by row and see every changed cell.
By Syed Mubashir Ali · Last updated
Compare two spreadsheets by key column
Try an example compares two versions of a tea price list. The second has its rows in a different order and a new Origin column, which on their own aren't changes. Rows are matched by SKU, found automatically, and the result is:
~ TEA-02 Stock: in → out − TEA-04 removed (Rooibos, 3.90, in) ~ TEA-01 Price: 4.50 → 4.75 + TEA-03 added (Earl Grey, 4.95, low, Sri Lanka) Column added: Origin
- Compare Two Lists: Compare a single column from each file: only in A, only in B, in both.
- CSV ↔ JSON Converter: Turn a CSV into JSON, then compare it with JSON Diff.
Excel files: what's read and how
Each cell is read the way Excel shows it by default: numbers to 15 significant digits, dates from the cell's date format (written as 2026-11-11, with the time when there is one), TRUE and FALSE, error codes such as #N/A, and formulas as their last calculated value. Rich text keeps its words, and merged cells keep their value in the top-left cell.
Older .xls workbooks and OpenDocument .ods files aren't read: save them as .xlsx or CSV first. Password-protected workbooks can't be opened either, because their contents are encrypted.
How to Use CSV & Excel Diff
- 1Paste the original table on the left and the changed one on the right, as CSV or rows copied from Excel or Google Sheets, or open a .csv or .xlsx file into either side. Try an example fills both with a price list.
- 2For an Excel workbook with several sheets, pick the sheet to compare on each side.
- 3Check Match rows by: it finds a key column (an ID, SKU, code or email with a different value in every row) automatically, or lines rows up by position when there isn't one. Choose another column if you prefer.
- 4Read the grid: changed cells show the old value struck through above the new one, added rows are green and removed rows red. Only rows with changes are shown until you switch to All rows.
- 5Leave Trim spaces and Numbers by value on so 4.50 matches 4.5; tick Ignore case if capitalisation doesn't matter.
- 6Download changes (CSV) saves every changed cell, added and removed row, and added or removed column.
Frequently Asked Questions
How do I compare two Excel files?
Open each .xlsx file with Open file, pick the sheet on each side if there are several, and the differences appear: changed cells shown old → new, added rows in green, removed rows in red. You can also copy rows straight from Excel or Google Sheets and paste them into the boxes.
How are rows matched?
By a key column when there is one: a column present on both sides with a different value in every row, preferring names like ID, SKU, Code or Email. Rows are then matched by that value wherever they are, so a sorted or reordered file doesn't look changed. Without one, rows are lined up by position, and an inserted row counts as one addition. Match rows by lets you choose.
What if the columns are in a different order or one was added?
Columns are matched by their header, so moving a column changes nothing. A column on only one side is listed as added or removed and shown in the grid, but it doesn't mark every row as changed.
Are 4.50 and 4.5 treated as different?
Not with Numbers by value on (the default): numbers are compared by value, so 4.50 equals 4.5 and 1,250 equals 1250. Untick it to compare cells exactly as written, which matters for codes with leading zeros.
Which files can it open?
CSV and TSV files in any common separator (comma, semicolon, tab or pipe, detected automatically) and Excel .xlsx workbooks, including dates, TRUE/FALSE and the last calculated value of formulas. Older .xls files and OpenDocument .ods files need saving as .xlsx or CSV first. Files can be up to 10 MB.
Can I save the differences?
Yes. Download changes (CSV) saves one line per changed cell, with the row's key, the column, the old value and the new value, plus a line for each added or removed row and column, ready to open in Excel or share.
Is my spreadsheet uploaded anywhere?
No. CSV text and Excel files are read and compared in your browser, so price lists, customer records and payroll exports never leave your device.
About CSV & Excel Diff
Two exports of the same spreadsheet rarely line up row for row: one is sorted differently, a column has moved, someone added a column at the end. A text diff then marks almost everything. CSV & Excel Diff compares the tables the way you would by eye, by matching each row to its counterpart by an ID column and each column by its header, then showing only the cells whose values changed.
It's built for price lists, stock and inventory exports, CRM and mailing-list exports, payroll and finance reports, and any CSV a system produces every day. Numbers are compared by value, so a price written 4.50 in one file and 4.5 in the other isn't a change, and Excel dates are read as dates rather than serial numbers.
Excel files are read in your browser by a small reader written for this tool, and CSV text never leaves the page: nothing is uploaded, which matters when the tables hold customers, salaries or orders.