Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Build an invoice from line items with tax and discount, and calculate the total.
This tool sums invoice line items (quantity × unit price), then applies a discount and tax in the standard order -- the same structure used by real invoicing software.
Add line items with a description, quantity, and unit price. Set a discount and tax percentage. Subtotal, discount, tax, and total all update instantly.
Subtotal = Σ (Quantity × Unit Price)
After Discount = Subtotal - (Subtotal × Discount %)
Total = After Discount + (After Discount × Tax %)
The calculator starts with two sample lines: 10 units of design work at 50 each, and 2 units of consulting at 100 each. Line totals are 500 and 200, so the subtotal is 700. Suppose you offer a 10 percent discount. The discount is 700 times 0.10, which is 70, leaving 630. With an 8 percent tax rate, tax is 630 times 0.08, which is 50.40, and the invoice total is 680.40.
The order matters. If tax were applied first and the discount afterward, you would get a slightly different figure. This tool always applies the discount to the subtotal first and then charges tax on the discounted amount. Whether that matches your situation depends on your local rules and how your sales are taxed, so confirm the correct treatment with your tax authority or accountant before relying on it.
It totals amounts; it does not create a formatted invoice document, assign invoice numbers, track payments, handle multiple tax rates on different lines, or calculate shipping. It also cannot tell you whether you are required to charge sales tax, VAT or GST, or which rate applies to your goods and services. Those rules depend on where you and your client are located and what you sell, so consult your local tax agency or a qualified accountant.
After -- tax is calculated on the discounted subtotal, the standard invoicing convention (you don't pay tax on the amount you didn't actually charge).
No. There is a single tax percentage for the whole invoice. If you need mixed rates, calculate each group separately and add the results by hand.
The discount field takes a percentage only. To reflect a flat discount, divide the discount by the subtotal and enter the resulting percentage, or reduce the relevant line price directly.
Software may round each line or each tax amount to the cent before adding, while this tool carries the full precision and rounds only for display. Follow whichever rounding method your records or local rules require.
Yes. Put the hours in the quantity field, including decimals such as 3.5, and your hourly rate in the unit price field.
Reference: Consumer Financial Protection Bureau