List ReconcileCompare two lists
Find missing values, count duplicates, and check the original rows.
3 business examples & CSV downloads
Fictional records. Loading an example replaces both lists and selects the matching columns.
A: shipments.csv → ID (column 1); B: receipts.csv → ID (column 2). Both use CSV with a header row.
00123 appears 4 times in A and 2 in B (+2). 00456 appears twice in each (0). Repeated IDs should show both values.
A: warehouse.csv → stock_code (column 1); B: catalog.csv → sku (column 2). Both use CSV with a header row.
0007 has counts 1/1; 0008 has 2/1. 0010 is only in A and 0009 only in B. Descriptions provide context and do not determine a match.
A: employee-export.csv → employee_id (column 1); B: employee-check.csv → employee_id (column 1). Both use CSV with a header row.
Three distinct IDs: 000042 has counts 2/1, 42 has 1/0, and 12345678901234567890 has 1/1. No digits or leading zeros should change.
Paste two lists above, or open CSV files and choose the columns to compare.
Comparison results
Repeated IDs appear more than once in A or B, including equal counts such as 2/2. Every original occurrence is retained.
Download includes all filtered results. Excel keeps IDs as text and includes source rows. CSV may be converted by your spreadsheet app.
| Value | Count A | Count B | A − B | Source rows |
|---|
No values match this filter.
“In both” checks presence. “Different counts” checks frequency, including values on only one side. Counts cannot identify which repeated transaction belongs to which.
A match doesn’t always mean the counts match.
If 00123 appears four times in A and twice in B, it is in both lists — with a count difference of +2. Compare unique values, then check their occurrences without throwing duplicates away.
Questions about comparing lists and CSV files
How do I compare two lists with duplicate IDs and find unequal counts?
Keep the duplicates in both inputs. In both checks whether a value appears on each side; Different counts compares occurrences. If ID 00123 appears four times in A and twice in B, its counts are 4 and 2 with an A minus B difference of +2. Repeated IDs also includes equal repeats such as 2/2. View rows shows every occurrence; the tool cannot identify which two individual transactions are unmatched. Work through the duplicate-ID example →
Can I compare CSV files without losing leading zeros or long IDs?
Yes. Values stay as text, so 00123 and 123 remain different, and long digit strings are not converted to numbers. Open the original CSV directly. If Excel already removed zeros or rounded digits and saved the file, the tool cannot restore them. Use Excel export for text cells or JSON for original strings. Keep identifiers intact →
How do I compare two CSV files with different column names or order?
Open one file on each side and select the corresponding key column independently, such as stock_code in A and sku in B. Check the separator, header setting, and first-record preview. Other columns remain available as source context. The selected fields must identify the same kind of thing. Compare differently arranged exports →
Can I find missing IDs and keep their original rows and other columns?
Load the full CSV rather than copying only its ID column. Select Only A or Only B, then use View rows to inspect the associated records and original line numbers. Excel and JSON downloads include source records for every filtered result. Copy values and the CSV summary do not include all original columns. Export differences with their context →
Why do values that look identical show as different in both lists?
Matching is exact by default. Case, outer spaces, embedded line breaks, and different Unicode characters can cause differences. Inspect View rows and Show whitespace as JSON escapes. Ignore outer whitespace and Ignore case are separate options; they do not remove internal spaces, normalize Unicode, or match similar names. Diagnose an unexpected mismatch →
How can I compare two Excel columns without leaving Excel?
Use an exact presence or occurrence-count formula in your workbook. Our Excel guide includes ready-to-copy SUMPRODUCT and EXACT formulas, explains range selection, and distinguishes a presence check from a duplicate-count check. The online tool accepts pasted cells or CSV exports; it does not open XLSX workbooks as input. Use the Excel formulas →
Do empty cells and CSV headers count as unmatched values?
A checked Header row setting removes the first parsed record from comparison. Physically blank lines are skipped. Empty selected keys are also skipped and their counts are reported. Space-only keys remain values under exact matching; turning on Ignore outer whitespace makes them empty and therefore skipped. Read the input and empty-key rules →
Can I compare CSV fields containing commas, quotes, or line breaks?
Yes, when the file uses valid quoted fields and the matching delimiter is selected. Use CSV, TSV, or Semicolon mode for structured data. A quoted field spanning several lines stays one record, and its source reference shows the original line range. Malformed quoting or inconsistent column counts produce a specific error. Check the file format →
Does downloading a comparison export all results or just the first page?
Download includes all results matching the current filter and search, across every page. Clear search if you want the complete filter result. Each input can contain up to 50,000 records and 5 MiB. Excel export cannot store a field longer than 32,767 characters; use JSON if you hit that limit. Choose the right report format →
Are employee lists, invoice IDs, and comparison results uploaded or saved?
The comparison and report generation run on your device. The application does not upload or save your input, filenames, or results. Leaving or reloading discards the working comparison; downloaded files and clipboard copies remain under your control. Share the example links to fictional sample data, never your current lists. Read how this site handles data →