Invoice total calculator
Calculate Invoice Totals with VAT and Discounts
Add multiple line items, apply a proportional discount, calculate VAT or GST by rate, and see the final invoice total.
How the invoice total calculator works
Add a description, quantity, unit price, and VAT or GST rate for each line. Optional discounts are allocated proportionally across line items. Shipping or another extra charge is added after tax and is not taxed by this calculator.
How VAT/GST is calculated on invoices
Each line's quantity is multiplied by its unit price to find its net amount. After any proportional discount is applied, the selected VAT or GST rate is calculated for that line. This supports invoices containing more than one tax rate.
How discounts affect invoice tax
Percentage and fixed discounts reduce the taxable line subtotal proportionally. VAT or GST is then calculated on each reduced line amount. Actual invoicing and discount rules vary by jurisdiction, so verify the treatment that applies to your invoice.
Example invoice calculation
An invoice with a 100.00 line at 20% VAT and a 50.00 line at 10% VAT has a 150.00 subtotal. A 10% discount reduces the taxable subtotal to 135.00. Tax is calculated on each proportionally discounted line, producing 18.00 and 4.50 tax, for a 157.50 total before any shipping charge.
Formulas
Line net: Quantity × unit price.
Discounted line net: Line net × (1 − proportional discount ratio).
Line VAT/GST: Discounted line net × VAT/GST rate ÷ 100.
Line gross: Discounted line net + line VAT/GST.
Grand total: Subtotal after discount + VAT/GST total + shipping or extra charge.
FAQ
Can different lines use different VAT or GST rates?
Yes. Enter a rate for each line. The calculator groups taxable values and tax amounts by rate in the summary.
Is shipping taxed?
Not in this calculator. The shipping or extra charge is added after VAT/GST. Tax treatment for shipping varies, so include taxable shipping as a separate line item when appropriate.
Can a fixed discount exceed the subtotal?
No. Fixed discounts are limited to the line subtotal, while percentage discounts are limited to 100%.
Does the calculator save invoice information or create a PDF?
No. Information remains in the current page only. There is no local storage, server storage, or PDF export.
Related tools
Check a single price with the VAT/GST calculator, remove included tax with the reverse VAT calculator, review profitability with the profit margin calculator, or estimate transaction costs with the payment fee calculator.