OD-matrix converter
Often OD-data comes in the form of an OD-matrix: the rows are the origins, the columns are the destinations and the trip counts are in the cells.
This utility can help you converting an OD-matrix dataset into the form suitable for FlowmapBlue by unpivoting the destinations.
Input OD-matrix TSV (tab-separated values)
Output TSV
You can copy-paste these data directly from and to your Google spreadsheet.