How to Find Missing Rows Between Two Files

You have two files. They should contain the same records — but do they? Finding missing rows is one of the most common data tasks, whether you're checking a data migration, auditing a report, or reconciling accounts.

The manual way (and why it's painful)

If you're new to file comparison, for the step-by-step CSV comparison guide, start there — then come back here for the missing-rows-specific approach.

The traditional way to find missing rows is using VLOOKUP in Excel to check each ID against the other file, then filtering for #N/A results. It works for small files but breaks down fast. Here's the full process:

1. Add a VLOOKUP in File A that looks up each ID in File B
2. Filter for #N/A results — those are the missing rows
3. Repeat in the other direction (File B looking up in File A)
4. Combine the results

This works for small files. But it's slow, error-prone, and gets complicated when your key spans multiple columns (e.g., matching on both name and date).

The fast way

The fastest way to find missing rows is to upload both files to a comparison tool that matches rows by key columns and shows you what's in one file but not the other. SheetPair does exactly this. Set your key columns, and in seconds you get:

• Only in File A — rows that exist in File A but not in File B
• Only in File B — rows that exist in File B but not in File A
• Plus matched rows and rows with differences, if you want the full picture

You can export just the missing rows as CSV or Excel with one click.

Common use cases

Data migration verification

After migrating records from one system to another, export both and compare. Missing rows = records that didn't transfer.

Report auditing

Got two reports that should show the same transactions? Upload both and instantly see which records are missing from each.

List deduplication

Have a master list and a new import? Find which records from the import are already in your master list and which are new.

Vendor reconciliation

Compare your purchase orders against vendor invoices to find orders that haven't been invoiced yet (or invoices without matching POs).

Multi-column keys

You can match rows using more than one column as the key — useful when a single column isn't enough to uniquely identify a row. For example, you might need to match on both Customer Name AND Invoice Date together.

SheetPair supports multiple key columns — just mark each one as a "key" in the column mapper. Rows must match on ALL key columns to be considered a match.

What about duplicates?

Duplicate rows are handled correctly. If File A has two rows with the same key and File B has one, SheetPair matches them and surfaces the extra row. No formula gymnastics needed.

Get started

Drop your two files at sheetpair.com and filter by "Only in File A" or "Only in File B" to see exactly what's missing. Free for files up to 1,000 rows.