Compare Excel Files for Differences Online — Free, No Upload, 1 Click
Spot added, removed and changed cells in seconds. No upload, no sign-up — file stays on device.
File A (older version)
Drop a .xlsx, .xlsm, or .xls file here, or click to browse
Processed locally · never uploaded
File B (newer version)
Drop a .xlsx, .xlsm, or .xls file here, or click to browse
Processed locally · never uploaded
How to Compare Two Excel Files Online
- Choose file A (for example the older export) and file B (the newer one). Each file is parsed locally in your browser as soon as you select it.
- Pick the sheet to compare in each file. Both default to the first sheet and can be compared even when the sheet names differ.
- Pick the key column in each file — the column that identifies a row, such as an ID or an order number. It defaults to column A.
- Keep “First row is a header” enabled (the default, shared by both files) when row 1 contains column titles.
- Click Compare files, then review the summary and download the diff report named {file-a}-vs-{file-b}-diff.xlsx.
Reading the Diff Report
The downloaded workbook contains two sheets. Summary gives you the counts at a glance; Changes lists every difference on its own row.
| Summary field | Meaning |
|---|---|
| File A / File B | The names of the two compared workbooks |
| Sheet | The sheet selected on each side |
| Rows A / Rows B | Data rows compared on each side (the header row is excluded) |
| Added | Keys that exist only in file B |
| Removed | Keys that exist only in file A |
| Changed rows | Matching keys with at least one different cell, plus duplicate-key flags |
| Duplicate keys | Total extra occurrences of repeated keys across both files |
| Changes column | Meaning |
|---|---|
| Change | added, removed, or changed |
| Key | The matched key value |
| Column | The changed column (header name or column letter); (row) for whole-row adds/removes; (duplicate key) for repeated keys |
| Old | The value in file A; for removed rows, the full row as a JSON string |
| New | The value in file B; for added rows, the full row as a JSON string |
How the Comparison Works
Rows are aligned by the key column, not by row position, so the same records match even when the two files are sorted differently. Each side can use a different key column — for example an “Id” column in file A and a “Customer No” column in file B.
Comparison is type-sensitive: the number 1 and the text "1" are treated as different values. Dates are normalized to ISO timestamps first, so the same date displayed differently (1/15/2024 vs 15-Jan) still compares as equal. When one sheet has extra non-empty columns, those cells appear as changed values with nothing (null) on the other side.
If a key appears more than once in a file, there is no unambiguous row-to-row match. Such keys are not compared cell by cell: the Changes sheet contains a single (duplicate key) row showing how many rows carry that key on each side (for example “2 rows” → “3 rows”), and the extra occurrences are counted under Duplicate keys.
When to Compare Two Excel Files
- Account reconciliation: match payments or invoices from two systems and list exactly what is missing or different on each side.
- Checking two exports: see what changed between yesterday’s and today’s CRM, e-commerce, or analytics export.
- Data migration validation: verify that every record survived an import or a system switch, with no altered amounts or dropped rows.
- Before a merge: identify conflicting and duplicate records before combining lists from two sources.
Good to Know
This tool outputs a difference report only. It never edits, uploads, or overwrites your original files — both stay exactly as they are on your device.
- All processing happens locally in your browser; your files never leave your device.
- The report is a value-level .xlsx rebuilt from the compared data: styles, merged cells, formulas (kept as cached values), and charts are simplified.
- Encrypted workbooks (a password is required to open them) cannot be read.
- Legacy .xls files are accepted as input; the report is always written as .xlsx.
Frequently Asked Questions
Is this Excel comparison tool free?
Yes — completely free, with no sign-up, no watermark, and no file-size limit for normal workbooks. Both files are processed in your browser and never uploaded.
How are rows matched between the two files?
By the key column you choose on each side — typically an ID, SKU, email, or order number. Rows with the same key are compared cell by cell; keys found on only one side are reported as added or removed.
What do added, removed, and changed mean?
Added keys exist only in file B. Removed keys exist only in file A. Changed rows share the same key but differ in at least one cell — every differing cell gets its own line in the Changes sheet.
Does it distinguish the number 1 from the text "1"?
Yes, comparison is type-sensitive, so 1 and "1" are different. Dates are normalized to ISO timestamps, so two equal instants displayed with different formats compare as the same date.
What happens when a key is duplicated?
Duplicate keys cannot be matched one-to-one, so they are not compared cell by cell. The Changes sheet gets one (duplicate key) line with the occurrence counts on each side, and every extra occurrence is counted in Duplicate keys.
Are my original files modified?
No. The tool only reads them and produces a separate diff report. The report contains values, not formatting, so cell styles in the report are simplified even though your originals stay untouched.
Which formats are supported?
.xlsx, .xlsm, and legacy .xls on both sides — the two inputs can even be different formats. The downloaded report is always a modern .xlsx file. Encrypted workbooks cannot be read.
Related Tools
Want the full walkthrough? Read How to Compare Two Excel Files for Differences — step-by-step instructions, the manual Excel method, and FAQ.
Need to fix the differences after reviewing the report?
Open the free online Excel editor