Hi Mala1,

Thanks for posting in the Community!

I'm afraid we cannot view the GST amount when splitting a transaction in QuickBooks Online. Assign the GST code per line item when splitting the transaction. Then, view the calculated GST amount. Click on the Categorised tab and locate the transaction to view. Here's how:

1. Click on the Categorised tab.
2. Locate and click the transaction.
3. From the opened transaction you'll see the GST amount calculated on the transaction.

You can also check on this article on how to manage your transactions in QuickBooks Online. 

Drop by again in the Community if youhave further questions about QuickBooks Online.