Guide · CSV files

Compare two CSV files without uploading them

Two exports that should list the same records rarely agree line for line. CSV Compare lines them up by a record ID you choose, such as an order, invoice or product number, and lists what is missing, changed or duplicated. It runs in your browser tab, and the files are not uploaded.

Try the free demo ↗ See licenses and prices ↗

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Before you start

• Two CSV or TSV files. Comma, semicolon and tab delimiters all work. Save the files as UTF-8 so that letters such as é or ø read correctly. Excel workbooks must be saved as CSV first: see how to compare two Excel sheets.
• A shared record ID. One column in each file must identify the same record, for example an order number. The column names may differ, such as record_id in one file and order_id in the other.
• One row per ID. When an ID appears twice in a file, the app reports a duplicate instead of guessing which row is right.
• The same scope. Export the same period with the same filters from both systems. Otherwise a difference may only mean that the exports cover different records.

Step by step

1. Load both files. Open the free demo and choose a left and a right file, or paste the CSV text. A preview of the first five rows shows how each file was read.
2. Check the delimiter. The app suggests comma, semicolon or tab, and quoted cells may contain delimiters. If the suggestion is unclear, choose the delimiter yourself.
3. Choose the decimal separator for each file if you will compare amounts: dot (1234.56) or comma (1234,56). It is never guessed.
4. Map the record key on both sides. If exactly one unique column is named like id, order_id or invoice_number, the app suggests it; review the suggestion.
5. Choose what to compare. Optionally map an amount and a currency column on both sides, and pair text columns such as status → state. Columns you leave out are listed as not compared.
6. Compare and review. Choose Compare exports, filter the review entries or search for an ID, then download the full report or the current view as CSV. To repeat the same check later, export a mapping profile: it stores your settings, not your rows.

Example: two product lists

A small business exports its product list from its web shop and from its stock system. Both files identify products by the same number, but the column names differ.

Map the record key sku to item_no, the amount price to unit_price with dot decimals on both sides, and the text pair status → state. No currency column is needed here.

That is 1 match and 4 review entries. The report shows where the files disagree; deciding which system is right stays with you.

sku,price,status
SKU-100,199.00,active
SKU-101,349.00,active
SKU-102,89.00,inactive
SKU-104,59.00,active

item_no,unit_price,state
SKU-100,199,active
SKU-101,379.00,active
SKU-102,89.00,active
SKU-103,120.00,active

What is compared, exactly

• Record IDs are trimmed and matched exactly. Case counts: ab-1 and AB-1 are different IDs.
• Amounts are compared as exact decimals, so 1250.00 equals 1250 and -12.50 equals -12.500. Thousands separators, currency symbols and scientific notation are not accepted; such a row is reported as invalid.
• Currencies must be three letters, such as NOK or EUR. They are trimmed and uppercased, and amounts are never converted.
• Text fields are compared character for character, including case, spaces and leading zeros: “01” differs from “1”.
• Duplicate IDs and invalid rows pause matching for that ID on both sides. Rows are never merged or summed.
• Columns you do not map are not compared. A match means only that the fields you selected are equal.

When a spreadsheet formula is enough

For a handful of rows, a lookup formula such as XLOOKUP or VLOOKUP may be the quickest check. A dedicated comparison helps when the check comes back every week or month, when duplicate IDs and malformed amounts should be flagged instead of silently matching the first row, and when you need a report you can hand to someone else.

Your files stay on your device

The comparison runs in your browser tab. While it reads and compares files, the app makes no network requests, saves no input to browser storage and contains no analytics. The demo page is delivered over the web like any other page, but your CSV contents are not sent anywhere. Downloaded reports contain your compared values, so store them as carefully as the source files. The full version is a ZIP file that you extract and open locally; it runs without a network connection.

Limits

• Free demo: up to 50 data rows and 2 MiB per file.
• Full version: up to 10,000 data rows and 2 MiB per file.
• Both: up to 100 columns per file and record IDs of up to 300 characters. The header row does not count as a data row.
• Not included: Excel workbooks (.xlsx), fuzzy matching, currency conversion, combining split invoices and automatic accounting entries.

Related: compare two Excel sheets via CSV · reconcile order or invoice exports · compare two supplier price lists · find records missing from one of two lists · compare a stock count with inventory · worked example with an expected report · format guide · see licenses and prices