It's really easy to split transactions between multiple categories with the Tiller Splitter add-on for Google Sheets.
Install the Tiller Splitter Add-on for Google Sheets here:
To split a transaction after you've installed the add-on:
- Select the entire row by clicking the row number
- Open the Google Sheets Add-on Menu
- Hover over Tiller Splitter
- Choose Split Transaction...
- Update the description, category and amounts to correspond to the way you'd like to see the transaction split.
- Ensure that the remainder totals $0.
- Click save to insert the split transactions.
Note: It's best practice to update the first line in the transaction splitter to use the amount that you want to split out as a separate category from the original transaction.