Invoice Total with Tax Calculator
Building an invoice that a client can reconcile means getting the order of operations right: discount first, then tax on what remains. This calculator does exactly that. You enter the subtotal of your line items, any discount you are giving, and the combined sales tax rate that applies at the point of sale, and it returns the taxable amount, the tax charged on it, and the final invoice total. Applying the discount before tax means the customer is taxed only on what they actually pay, which is the usual treatment for a discount on the goods, although rules can vary by state and by the type of discount. Because sales tax rates differ widely across the United States, with city and county add-ons stacking on the state rate, the rate is left fully editable so you can enter the exact combined figure for your jurisdiction. The results break out the taxable amount and the tax separately, so you can show a client precisely how the final number was reached. Every figure is computed deterministically from the formula shown below, with a worked example that reconciles exactly to the calculator defaults so you can confirm the total before you send the invoice.
Discount first, then tax: total = (subtotal - discount) + tax. A $2,000.00 subtotal less a $100.00 discount is taxed at 8.25% ($156.75) for an invoice total of $2,056.75.
Invoice total formula
Taxable amount = Subtotal - Discount
Sales tax = Taxable amount x Tax rate
Invoice total = Taxable amount + Sales tax
The discount is applied before tax, so the customer is taxed only on what they actually pay. A larger discount lowers both the taxable base and the tax.
Worked example
An invoice has a 2,000 dollar subtotal, a 100 dollar discount and an 8.25 percent tax rate.
- Taxable amount = 2,000 - 100 = 1,900.00
- Sales tax = 1,900 x 0.0825 = 156.75
- Invoice total = 1,900.00 + 156.75 = 2,056.75
The invoice total is 2,056.75 dollars. These are the calculator's default inputs, so the result above matches the widget exactly.
Tax on a 1,900 dollar taxable amount
The same taxable base produces a different total as the combined rate changes.
| Tax rate | Sales tax | Invoice total |
|---|---|---|
| 6.00% | $114.00 | $2,014.00 |
| 7.00% | $133.00 | $2,033.00 |
| 8.25% | $156.75 | $2,056.75 |
| 9.00% | $171.00 | $2,071.00 |
Invoicing and small-business money basics: US Securities and Exchange Commission, Investor.gov.
Invoice total calculator: frequently asked questions
How is an invoice total calculated?
Start with the subtotal of line items, subtract any discount to get the taxable amount, apply the sales tax rate to that amount, then add the tax back to reach the final total. Applying the discount before tax means the customer is taxed only on what they actually pay, which is the usual order for a percentage or dollar discount on the goods.
Is tax applied before or after the discount?
In most cases a discount on the goods is applied first, and tax is charged on the reduced amount. This calculator follows that order: taxable amount equals subtotal minus discount, and tax is computed on the taxable amount. Rules can vary by state and by whether the discount is a manufacturer coupon, so check your local sales tax guidance for edge cases.
What sales tax rate should I use?
Use the combined state and local sales tax rate that applies at the point of sale or delivery, which can include city and county add-ons. Rates differ widely across the United States, and some items are exempt. This tool leaves the rate fully editable so you can enter the exact combined rate for your jurisdiction.
Does the discount reduce the tax?
Yes, when the discount lowers the taxable amount. Because tax is charged on the subtotal minus the discount, a larger discount produces both a lower taxable base and a lower tax. That is why the calculator shows the taxable amount and the tax separately, so you can see the effect.
What is the invoice total formula?
Taxable amount equals subtotal minus discount. Tax equals taxable amount multiplied by the tax rate. Invoice total equals taxable amount plus tax.
Official sources
- Invoicing and small-business money basics: US Securities and Exchange Commission, Investor.gov. As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.