Tax on an Invoice: Added on Top or Included?
Facts last checked October 24, 2026
When you charge sales tax, such as VAT, GST or state sales tax, you have two ways to show prices on an invoice. Either the tax is added on top of your price, or the price you quote already includes the tax. Both are common. What matters is that the invoice makes it clear which one you mean, and that the arithmetic is right.
The two methods
Tax added on top (prices exclude tax). You quote a price before tax, then add tax to get the total.
- Price: $200.00
- Tax at 8.25%: $16.50
- Total: $216.50
Tax included in the price (prices include tax). You quote the price the customer pays. The tax is part of it, and you work it out backwards.
- Price including tax: $216.50
- Tax inside the price at 8.25%: $16.50
- Price before tax: $200.00
Notice that both examples describe the same sale. Only the way it is presented differs.
Which should you use?
There is no single answer. These are common patterns rather than rules:
- Invoices between businesses often show prices without tax, then add the tax, because the buyer may be able to reclaim it.
- Prices aimed at consumers are often shown with tax included, so the number on the price tag is what they pay.
Some countries require one approach for certain kinds of sales. If you are not sure, ask your tax authority or an accountant. Whichever you choose, say it on the invoice, for example “Prices include tax” or “Tax is added to the subtotal”.
The arithmetic
Added on top
Tax = price × rate. Total = price + tax.
For a rate of 18%: tax = price × 0.18, so a $100.00 item gives $18.00 of tax and a total of $118.00.
Included in the price
Price before tax = price including tax ÷ (1 + rate). Tax = price including tax − price before tax.
For a rate of 18% on a $100.00 price that includes tax:
- Price before tax: 100.00 ÷ 1.18 = 84.7457…, which rounds to $84.75
- Tax: 100.00 − 84.75 = $15.25
- Total: $100.00
A common mistake is to take 18% of $100.00 and call that $18.00 of tax. That would be correct only if the $100.00 were the price before tax. When the tax is inside the price, the tax is a smaller share of the total: 18% of the price before tax, which is about 15.25% of the price including tax.
Several tax rates on one invoice
Some invoices mix rates. For example, one item might be taxed at 5% and another at 18%, and a third not taxed at all. Show each rate separately in the tax summary so the client can see how much tax each rate produced:
| Rate | Taxable amount | Tax |
|---|---|---|
| 0% | $20.00 | $0.00 |
| 5% | $120.00 | $6.00 |
| 18% | $50.00 | $9.00 |
Our invoice generator groups the tax by rate in this way and lists each rate on the invoice.
Rounding: line by line or on the total?
Tax is almost never a whole number of cents, so you have to round. The question is where. Take three items of $0.10, each taxed at 5%:
- Rounding each line: 5% of $0.10 is $0.005. Rounded to the nearest cent (halves rounded up) that is $0.01. Three lines give $0.03 of tax.
- Rounding the total: the three items add to $0.30. 5% of $0.30 is $0.015, which rounds to $0.02.
The difference is one cent here, but on invoices with many lines it can grow. Neither is “wrong” in the abstract: tax authorities and accounting software handle it in different ways, and some countries specify one. The key is to be consistent and to make sure the invoice adds up as printed.
Our invoice generator rounds the tax on each line, halves rounded away from zero, so the lines you see always add up exactly to the totals. If your country requires rounding on the invoice total instead, check the figures against your accounting software before you send.
Discounts and tax
If you give a discount, it normally comes off before tax is calculated, so the customer is taxed on the lower price. Our tool applies line discounts first, then spreads any invoice-wide discount across the lines in proportion to their value so the tax on each line stays correct.
Checklist
- Say clearly whether prices include tax or not.
- Show the tax rate next to each taxed line.
- Show the tax amount in its own line, or one line per rate.
- Make sure the lines and totals add up exactly.
- Include your tax registration number if you are registered.
Sources and notes
This guide is general information, not tax or legal advice. Rates, rounding rules and what you may charge tax on differ by country and by what you sell. For what a tax invoice must show, see what to include on an invoice.
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