Lookup Tool
Add a column to your file by looking up values from a reference table. Like Excel's VLOOKUP — works with CSV, Parquet, Excel, JSON, and more. Everything runs in your browser.
Main file
Lookup table
How to use the Lookup Tool
- Load your main file on the left and the lookup table on the right. CSV, TSV, Parquet, JSON, NDJSON, Arrow, YAML and Excel files work, by browsing or by dragging them onto each panel, and the two files can be different formats.
- Pick the matching columns: the key column in the main file and the column it should equal in the lookup table.
- Pick the return column from the lookup table and, if you like, give the new column a different name.
- Choose what happens to rows with no match: keep them with a blank value, or remove them. Then click Look up.
- Check the matched and unmatched counts and the preview of the first 200 rows, then export the result as CSV, Parquet, JSON, TSV, NDJSON or Excel.
Worked example
An order export has product codes but no product names. A second file maps each code to a name. You want the name added to every order.
Input: main file (orders.csv) and lookup table (products.csv)
orders.csv
order_id,sku,qty
1,A100,2
2,B200,1
3,C300,5
products.csv
sku,product_name,price
A100,Desk lamp,25
B200,Chair,80Settings
- Match main column: sku = lookup column: sku
- Return column: product_name (new column name: product_name)
- Unmatched rows: Keep (fill with blank)
Output (orders_lookup.csv)
order_id,sku,qty,product_name
1,A100,2,Desk lamp
2,B200,1,Chair
3,C300,5,
2 rows matched, 1 row unmatchedC300 is not in the lookup table, so order 3 keeps a blank product_name. With "Remove" selected instead, order 3 would be dropped from the result. Row order in the output can differ from the input file.
Frequently Asked Questions
How is this different from VLOOKUP or XLOOKUP in Excel?
It does the same job, an exact-match lookup, but across two separate files in any supported format and without writing or copying formulas down thousands of rows. The result is a new file with the extra column filled in.
What if a key appears more than once in the lookup table?
VLOOKUP returns the first match. This tool returns every match, so a main row whose key appears twice in the lookup table shows up twice in the result. Run Find Duplicates on the lookup table first if you are not sure its keys are unique.
Does matching ignore case or extra spaces?
No. Values must match exactly as text. "A100" does not match "a100" or "A100 " with a trailing space. Numbers are compared as text too, so 42 matches "42". Clean the key columns first with the Trim or Convert Case tools if needed.
Can I bring back more than one column?
Each run adds one column. To add another, export the result, load it as the main file and run the lookup again. To bring in every column from the second file at once, use Join Files.
Are my files uploaded?
No. Both files are loaded and joined inside your browser tab. Nothing is sent to a server.
Related tools
Join Files
Join two files on a key and keep every column from both, with inner, left, right or full joins.
Find Duplicates
Check that your lookup keys are unique before you run a lookup.
Remove Duplicates from CSV
Drop repeated rows so each key appears only once.
Trim CSV Whitespace
Remove leading and trailing spaces that stop keys from matching.
SQL Query Tool
Write your own join when you need more control than a lookup gives.
Excel Sheet Extractor
Pull the reference table off a specific sheet of a workbook.
Data Profiler
Count nulls in the new column to see how many rows failed to match.