Group Concatenate Excel Files Online

What does group concatenate do to a Excel file?

It collapses multiple rows that share the same group-by column value into a single row. The values from the chosen column are joined into one delimited string — for example, all product names for each customer in a single cell.

Can I control the order of values inside each group when concatenating a Excel file?

Yes. Set the Order By column and choose ascending or descending. Without an order, values within each group appear in their physical storage order, which may not be deterministic.

What separator should I use when concatenating values in a Excel file?

Common choices are comma-space (", "), pipe (" | "), semicolon ("; "), or a newline ("\n"). Avoid using a separator that also appears inside the values — or use the SQL Query tool to wrap values in quotes before concatenating.

Is my data private?

Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.

What is the maximum file size?

The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.