Invoice Total Calculator: From Line Items to Amount Due

Write each line as quantity times unit price and join them with plus signs. For example, 3 items at $120, 2 at $45.50, and 1 at $89.99 becomes 120*3 + 45.5*2 + 89.99*1.

Most invoices apply the discount to the pre-tax subtotal, then add tax on the discounted amount. That is why the example multiplies by (1 - 0.10) first and then by (1 + 0.0825). If your jurisdiction taxes the full subtotal, swap the order.

Yes. Subtract the fixed amount from the subtotal, for example (120*3 + 45.5*2 + 89.99*1 - 50), then multiply by (1 + tax rate).

No. All calculations run in your browser and nothing is uploaded, logged, or saved on a server.

It is a fast, accurate way to verify invoice totals and catch arithmetic errors. For official records, always confirm the final figures in your accounting or invoicing system.