Invoice Total Calculator
About this calculator
The Invoice Total Calculator adds up line items and applies tax, discount and shipping to produce the final invoice amount. Enter each item with a description, a quantity and a unit price, then set the tax rate, a percentage discount and any shipping or fees.
It is a calculator rather than a document builder, so use it to check a total before you issue an invoice, to quote a price, or to verify a supplier's bill. It supports dollars, rupees, pounds and euros.
How to use it
- Enter each item with its quantity and unit price. Use + Add Item for more rows.
- Choose a Currency.
- Set the Tax Rate, a Discount % and any Shipping or Fees.
- Read the subtotal, discount, tax and total.
How the total is computed
Subtotal = Σ (Quantity × Rate). Discount = Subtotal × Discount %. Tax = (Subtotal − Discount) × Tax %. Total = Subtotal − Discount + Tax + Shipping. Tax is charged on the discounted amount and, in most places, shipping is outside the discount.
Worked example
Web design $2,500, hosting setup $500, domain $899, 18% tax
| Subtotal | $3,899.00 |
| Tax at 18% | $701.82 |
| Total | $4,600.82 |
With a 10% discount the discount would be $389.90, tax would drop to $631.64 and the total to $4,140.74.
Tips and common mistakes
- Check whether your tax applies to shipping in your state or country.
- Apply discounts before tax. Tax is then charged on the amount the client actually pays.
- Round once, at the total. Rounding each line can move the total by a few paise.
- State the currency on the invoice if you work with international clients.
- Keep the calculation for reference if the client queries the total.
Frequently asked questions
How do I calculate an invoice total?
Add up quantity times rate for each line, subtract discounts, add tax and then add shipping or fees.
Is tax calculated before or after discount?
After the discount, on the amount the customer actually pays.
Can I use it for GST?
Yes. Set the tax rate to 18%, 5% or whichever applies.
Does it add shipping before tax?
Shipping is added after tax in this calculator. If your law taxes shipping, include it as a line item instead.
Can I change the currency?
Yes, choose from dollars, rupees, pounds and euros.
Does it create a printable invoice?
No. For that use the Invoice Maker.