Compare Two Financial Files: A Simple Reconciliation
Two versions of a ledger, a position file or a trade list rarely match. Here is how to see exactly what differs.
Reconciliation means checking that two sources agree. It might be a trade list from your system and one from a counterparty, a ledger before and after an adjustment, or this month and last month of the same report. Doing it by eye or with a VLOOKUP is slow and misses changes.
Data Comparison matches the files by a key column. Choose the column that identifies a row, such as a trade ID or an account number, and the tool shows the rows that were added, the rows that were removed and the rows where a value changed, with the changed cells marked. You can use more than one column as the key and export the differences.
Prepare the files first or you will see false differences. Make sure the key is unique in both files and use the same format for dates and numbers. Data Comparison can trim spaces and ignore upper and lower case for you, and it has a number tolerance, so a difference of 0.01 can be accepted as a match. Data Transformation can standardise both files first in a few steps.
Read the result carefully. A changed row can be a real correction or a formatting difference, a removed row can be a deletion or a different key, and a decimal rounding difference can look like a break. Set the number tolerance before you start, and write it down with the result.
The files are compared in your browser and are not uploaded, which helps when they hold client or account data. A comparison tool shows what differs. It does not tell you which file is right, so confirm any break against the source system.
Related tool pages
- Compare Two CSV Files: Compare two CSV or Excel files by a key column and see added, removed and changed rows. Free, runs in your browser.
- Compare Two Excel Files: Compare two Excel (.xlsx) files by a key column and see every added, removed and changed row and cell. Free, and your files stay in your browser.
- CSV Diff Tool: Find the differences between two CSV files online: which rows were added, removed or changed, cell by cell. Free, in your browser.
How to use the Data Comparison: step by step
- Open Data Comparison and load both files.
- Choose the key column that identifies each row.
- Review the added, removed and changed rows.
- Download the differences and confirm each break at the source.
When to use the Data Comparison
- Compare two versions of a ledger or position file
- Check a trade list against a counterparty file
- See what changed between two monthly reports
- Check a file after a system migration
Example
Input: before.csv + after.csv, key = id
Output: Added 3 · Removed 2 · Changed 5
Frequently asked questions
Can the files be different formats?
Yes. A can be a CSV and B an Excel file. Columns are matched by name. JSON and Parquet files are not supported here, so convert them to CSV first.
How does Data Comparison find differences?
It matches rows by a key column, or by the first two columns, and shows which rows were added, removed or changed, down to the cell. It works with CSV and Excel files.
Tip: Standardise dates, spaces and number formats in both files first, otherwise formatting shows up as differences.