Compare Files
Compare two versions of a file. See which rows are new, removed, changed, or unchanged.
By Operelio team
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What it does
Compares two files using a shared key column. Every row is labeled as new (only in File B), removed (only in File A), changed (in both but with different values), or unchanged.
Rows are matched by the key column, not by position, so the comparison stays correct even when rows are added, removed, or reordered between versions.
If one file has a column the other does not (a new export field, for example), that is reported once as a note. It never counts rows as changed, so a column difference cannot drown out the real value changes.
How to use it
Upload two files
File A is the older version. File B is the newer one.
Pick the key column
Select the column in each file that identifies each row, like an ID or email. You can match on more than one column.
Choose output mode
Full diff (default), new rows only, changed rows only, removed rows only, or a counts-only summary. All five are on every plan.
Run the comparison
Click Compare files. Operelio writes an output file. Most modes include a Change type column showing each row's category; summary mode produces a counts table.
Output modes
| Mode | What it includes |
|---|---|
| Full diff | All rows from both files, with a Change type column and a Changed columns column spelling out each edit (e.g. Plan: Free -> Starter). Unchanged rows are included by default (toggle off to exclude them). |
| New rows only | Just the rows that appear in File B but not File A. |
| Changed rows only | Just the rows that exist in both files but have different values, with a Changed columns column spelling out each edit. |
| Removed rows only | Just the rows that appear in File A but not File B. |
| Summary | A two-column table with counts: how many new, removed, changed, and unchanged. Downloads as CSV. |
Color-coded Excel output
When you download as .xlsx, the output is color-coded: green rows are new, red rows are removed, yellow rows are changed. Individual cells that changed within a row are highlighted in a darker yellow so you can spot exactly what is different.
What the results show
The results page shows: rows from File A, rows from File B, counts for new, removed, changed, and unchanged rows, which key columns were used, and a breakdown of which columns had the most changes. The changed-columns list tells you at a glance which columns have the most differences.
Frequently asked questions
What if the two files have different columns?
Operelio starts with all columns from File A, then appends any columns that only exist in File B. Missing values are left blank.
What plan do I need?
Every output mode, multi-column matching, and the color-coded Excel output are on every plan, including Free. What changes with the plan is how many rows and how large a file you can put through.
Ready to get started?
Upload a file and run your first transformation. Free, no credit card required.