Compare two CSV versions
Find added, deleted and modified records by matching unique IDs in the first column. Preview the changes and download a four-sheet Excel report.
This page provides an English CSV comparison tool. Other HaoToolbox tools are available in Traditional Chinese.
Choose your two versions
UTF-8 CSV only. Each file: up to 128 KiB, 500 records including the header, and 2–20 columns.
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Copies five counts only. Source filenames and data are excluded from the summary.
Prepare the files before comparing
Both versions must have exactly the same headers and column order. Move your ID column to the first position in both files before using this pilot.
- The first column must contain a nonblank, unique ID for every data record.
- IDs and values are compared as exact strings. Leading zeros, whitespace and formula-like text are preserved. Values are not trimmed or converted to numbers.
- Record order is ignored. A matching ID with a changed value is modified; an ID found only in the new version is added; one found only in the old version is deleted.
- Headers must be nonblank, unique, and must not use the reserved name
__record. - Up to 2,000 changed fields and an 8 MiB report are supported. Oversized or malformed input stops processing without a partial report.
Read the report
The workbook contains Summary, Added, Deleted and Modified sheets. Previews show at most 10 data records per sheet; the download contains the complete accepted result. Preview values use quoted string notation so spaces, quotes and newlines remain visible.
Report record numbers include the header as record 1. They are not physical text line numbers. The synthetic example includes one added record, one deleted record, one modified record, two unchanged records and two changed fields.
Data and privacy
Selected CSV filenames and contents are processed in this browser and are not uploaded. This tool adds no persistent browser storage. Loading the page and its scripts still sends normal web requests to the site host; this is not an offline application.
The saved Excel report includes source filenames, SHA-256 hashes and added, deleted or modified source values. Review these details before sharing a report. Use synthetic or public non-sensitive data when trying the tool. Native desktop Excel display has not been verified.
Copy difference summary writes only five counts to your clipboard after you choose that action. Your clipboard and files you have already saved remain until you replace or delete them yourself.
Clear files and results invalidates current work, empties the preview and revokes its download link. Leaving the page also revokes that link. Neither action deletes files already downloaded or erases your clipboard.
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