Invoice Total Calculator
Get the subtotal, discount, GST and grand total for an invoice line from quantity and rate.
- Subtotal
- —
- Discount
- —
- GST
- —
Arithmetic only. Check tax treatment with your accountant.
What is the Invoice Total Calculator?
The invoice total calculator works out the grand total for an invoice line. Enter quantity, rate, discount percentage and GST percentage to see the subtotal, the discount, the GST amount and the final amount payable.
How it works
Subtotal equals quantity times rate. Discount equals the subtotal times the discount percentage divided by 100. GST is charged on the discounted amount, using the rate you type. Grand total equals the subtotal minus the discount plus GST.
How to use it
- Enter the quantity and the rate per unit.
- Enter any discount percentage.
- Enter the GST rate that applies to the item.
- Read the subtotal, discount, GST and grand total.
Invoice Total Calculator — FAQ
Is GST charged before or after the discount?
This tool applies GST on the amount after discount, which is the usual treatment for a trade discount shown on the invoice. Confirm with your accountant.
Can I have several items?
This works for one line. For several lines, run each one and add the grand totals, or use billing software.
Does it know the GST rate?
No. You enter the rate, because it depends on the item and the current rules.