Find the final invoice price after both a discount and GST are applied.
The discount is applied first, then GST is calculated on the discounted price — matching how real invoices are raised.
Final price: (Price − Discount) × (1 + GST rate)
Is GST calculated before or after the discount?
After. When a discount is shown on the invoice at the time of sale, GST is charged on the lower, discounted price — not the original price.