Invoice Total Calculator

Written byOleh Soloninupdated 5 October 2026

Quantity

Unit price

Discount, %

Shipping

VAT, %

VAT in the price

Result

To pay$48,600.00
Excluding VAT$40,500.00
VAT$8,100.00
Discount$4,500.00
Before the discount$45,000.00
Total per unit$4,860.00

On top of, or already inside

Calculates an invoice total with a discount and shipping, adding tax on top or extracting it from a price that already includes it.

Two invoices with the same numbers can differ by twenty percent, depending on one detail: whether the tax is added to the price or already sitting in it. Getting that backwards is the commonest invoicing mistake there is.

Extracting tax is not the same as subtracting it. Twenty percent of a tax-inclusive total is not the tax; the tax is the total divided by 1.2 and subtracted, which is a sixth rather than a fifth.

How to use

Enter the quantity and the unit price.
Give the discount as a percentage, if there is one.
Add shipping — it sits outside the base the discount applies to.
Say whether VAT is added on top or already inside the price: the whole calculation turns on it.

What discount and VAT do to the total

Each row is a run of this calculator at 10 units of 4,500 with VAT at 20 percent. The discount comes off the pre-tax figure, so it reduces the tax as well.

The last row is the same invoice with VAT extracted from the price rather than added to it. The total drops from 48,600 to 40,500: a price of 4,500 means 4,500 plus tax in one reading and 3,750 plus tax in the other. That is not a formatting nicety: 8,100 is a sixth of the first total and a fifth of the second.

Runs of this calculator at 10 units of 4,500 with VAT at 20%.
Discount	Before discount	Discount	Base	VAT	Total due
0%	45,000	0	45,000	9,000	54,000
10%	45,000	4,500	40,500	8,100	48,600
20%	45,000	9,000	36,000	7,200	43,200
10%, VAT inside	45,000	4,500	33,750	6,750	40,500

What this calculator shows

The total to pay and the net amount without tax
The tax and the discount in money
The effective total per unit

What to keep in mind

The discount applies before the tax, which is the normal order: tax is charged on what is actually paid.
Shipping is treated as taxable along with the goods, as it usually is when it is part of the same supply.

FAQs

How do I extract tax from a total?

Divide by 1 plus the rate and subtract. At twenty percent, the tax inside a total is the total divided by six, not a fifth of it.

Does the discount come before or after tax?

Before. Tax is charged on the amount actually payable, so the calculator takes the discount off the pre-VAT figure and charges the tax on the smaller base. That is why a 10 percent discount also cuts the VAT, from 9,000 to 8,100.

Is shipping taxable?

Usually, when it is part of the same supply. A separately contracted carrier is a different transaction with its own treatment.

Why does the per-unit figure differ from the price?

Because it spreads the discount, the shipping and the tax across the units. It is the number to compare between quotes.

What does “VAT inside the price” mean?

That the stated price already contains the tax and it has to be extracted by dividing by 1.2 at a 20 percent rate. The same invoice comes to 40,500 in that mode instead of 48,600 — a fifth of a difference.

Worked example

Ten units with a discount

Input: 10 × 4,500, a 10 percent discount, 20 percent tax added on top

Output: 48,600 to pay, of which 8,100 is tax

Note: Had the same 4,500 been tax-inclusive, the total would be 40,500 with 6,750 of tax inside it. Same numbers, an eight-thousand difference.

Useful links

All tools in Business and warehouse calculators

Invoice Total Calculator

Result

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