I'm here to make sure your GST tax is properly calculated in QuickBooks Online (QBO), @vipinraj-jjaudit.
I've tried replicating your invoice using the 18% GST tax rate. It seems that your CGST and SGST taxes do have wrong calculations.
The GST can be calculated by multiplying the Taxable amount on the GST rate. If CGST & SGST is to be applied, then both of its amounts are half of the total GST amount.
This means that if your taxable amount is 2148.19, then your tax should be 386.6742 using the GST 18% tax rate. This also means that both CGST and SGST should be 193.3371 or 193.34 once round off to the nearest hundreds. You can refer to the screenshot below for the correct tax calculation.
It's possible that there's an issue within your browser that causing this unexpected behavior. I'd recommend performing some basic troubleshooting steps to fix it.
First, access your QBO account in a private window. This mode doesn't record any activity on your local device no trace can be found on your web browser. Here's how:
If the tax calculation is now showing the correct amount, then you can go back to your regular browser and clear its cache or try using a different supported browser. It could be a temporary issue with QuickBooks and the current browser that you use.
If you're still getting the same issue, I'd recommend reaching out to our customer support. This way, they can check your account and verify the cause of the concern.
If there's anything else you need, you're always welcome here in the Community to post again. We'll be always around ready to help.