Excel Diff

Compares two Excel/CSV files and tells you which rows were added, removed and changed. Produces a colour-coded report.

What it does

Use this to compare last month's CRM export to this month's, to spot the differences between a draft and a final report, or to audit what changed between two versions. No more row-by-row manual checking.

How to use

  1. Pick the old/base file under Base Version.
  2. Pick the new file under Comparison Version.
  3. Pick the sheet to compare on each side.
  4. Pick a Unique Key column (e.g. order_id, customer_id). Used to match rows.
  5. Pick a Diff Method: Smart Auto-Detect, Key-Based or Positional.
  6. Tick the report options you want.
  7. Click Run.

You get a colour-coded Excel report: added rows green, removed rows red, changed rows yellow.

Diff methods

MethodWhen to pick it
Smart Auto-DetectFirst choice. Uses key-based if a good key exists, otherwise positional.
Key-BasedMatches rows by the same key (e.g. order_id) even when row order differs. Most accurate.
PositionalRow 1 vs row 1, row 2 vs row 2. One added/removed row throws off the alignment.

Unique Key

The unique key is a column that identifies each row uniquely. Order ID, customer ID, product code. Picking the right key is what makes the comparison meaningful.

Report options

  • Only Export Differences: Skips identical rows in the report, just shows changes. Useful for big files.
  • Generate High-Level Summary Sheet: Adds a summary page: how many rows added, removed, changed.

Examples

Monthly CRM comparison: January CSV as Base, February CSV as Comparison, key customer_id, Smart Auto-Detect, run. Shows which customers were added, dropped, or updated.

Draft vs final report: v1.xlsx as Base, v2.xlsx as Comparison, key product_code, run. Shows which product prices changed.

Two sheets in the same file: Pick the same file on both sides, then pick different sheets. Shows the diff between Sheet1 and Sheet2.

Database backup verification: Old backup vs new backup as an integrity check.

Watch out

  • Needs exactly two files, not one and not three.
  • The unique-key dropdown comes from the Base file only. If the new file does not have that column, you will get an error.
  • In Positional mode, one inserted row makes all the following rows look "changed". Key-based is safer.
  • Very large files (100K+ rows) may take a while.
  • Encrypted Excel files are not handled.

License

Free tier has a monthly diff cap. Office plan removes it.