Question 1

How do I calculate invoice total with tax and discount?

Accepted Answer

First sum all line item totals to get the subtotal. Apply any discount (percentage or fixed amount) to the subtotal. Then apply the tax rate to the discounted subtotal. The final total is: Subtotal − Discount + Tax. This calculator handles all steps automatically.

Question 2

Should discount be applied before or after tax?

Accepted Answer

In most regions, discounts are applied before tax — the tax is calculated on the net (discounted) amount. This is the standard method used by most invoicing software and retail. This calculator applies discount first, then calculates tax on the reduced subtotal.

Question 3

Can I use this for quotes and estimates?

Accepted Answer

Yes. The invoice calculator works for any pricing document — invoices, quotes, estimates, purchase orders, or receipts. Simply add line items, set the tax rate, and optionally a discount to see the final total instantly.

Question 4

Is my invoice data private?

Accepted Answer

Absolutely. All calculations happen in your browser. No line items, prices, or business data are ever sent to any server. The tool works completely offline after loading.