How to Calculate Prices Including and Excluding VAT?

A customer asks, "What's the total?", and you know the price excluding VAT. Or vice versa: the tag on the shelf reads 1,200 TL and you need to figure out how much of that is VAT.

These are two different operations, and when mixed up, the resulting error might seem minor, but it piles up as the number of invoices grows.

Direction 1: From Exclusive to Inclusive

You have the amount excluding VAT and want to find the total. This is the easy direction:

VAT inclusive = VAT exclusive × (1 + rate)

For a 20% rate and a 1,000 TL item: 1,000 × 1.20 = 1,200 TL. The VAT amount is 200 TL.

Direction 2: From Inclusive to Exclusive

This is where the actual mistake happens. You have 1,200 TL including VAT and want to find the VAT. Most people take 20% of 1,200: 240 TL. This is wrong.

Because VAT is a percentage of the exclusive amount, not the inclusive amount. The correct operation is division:

VAT exclusive = VAT inclusive ÷ (1 + rate)

1,200 ÷ 1.20 = 1,000 TL. And the VAT is 1,200 − 1,000 = 200 TL. Not 240.

The 40 TL difference might seem insignificant for a single invoice. For a business recording three hundred receipts this way every month, your deductible VAT will systematically bloat.

Multipliers by Rate

Instead of memorizing, keep this table handy:

The last column is a handy shortcut: it finds the VAT directly from the VAT-inclusive amount. For 20%, dividing the inclusive amount by 6 gives the same result (20/120 = 1/6).

Which rate applies to which goods and services is a different topic. We covered that in our article on VAT rates.

Rounding: A small discrepancy, a big headache

In retail, prices are generally set as VAT-inclusive round numbers, like 149.90 TL. When you convert this amount to exclusive, you get a fractional number: 149.90 ÷ 1.20 = 124.9166...

The danger here is rounding each line item separately and then adding them up. If you lose one cent on each line in a ten-item invoice, the invoice total and the paid amount won't match by a few cents. The customer might not notice, but you will struggle during reconciliation.

The correct approach: perform intermediate calculations with full precision, and apply rounding only at the display stage. Software does this anyway — this is a trap that people calculating manually in Excel fall into.

If there is a discount, sequence matters

You are giving a customer a 10% discount. Will you apply the discount before or after the VAT?

The answer is clear: discount first, then VAT. VAT is calculated over the net amount after the discount has been deducted.

• List price (exclusive): 1,000 TL
• 10% discount: −100 TL → taxable base 900 TL
• 20% VAT: 180 TL
• Invoice total: 1,080 TL

The discount should appear as a separate line on the invoice; using a discount line instead of directly lowering the unit price is both transparent and useful for future analysis. We expanded on this topic in our article on discounts and maturity differences.

Which one should you quote when giving prices?

If you are selling to an end consumer, prices are announced including VAT; they are expected to pay the exact figure they see on the tag.

If you are quoting a corporate client, speaking in VAT-exclusive terms is standard — because the other party will treat VAT as deductible, so it's not a cost for them. Adding the phrase "prices do not include VAT" to your quote prevents later disputes.

If you are selling to both audiences at once, decide which baseline your price list is built on and stay consistent. The most frequent confusion arises when the same product is priced inclusive to one person and exclusive to another.

Frequently Asked Questions

Why is taking 20% of a VAT-inclusive amount wrong?

Because the 20% rate applies to the exclusive amount. Since the inclusive amount already contains the VAT, taking 20% of it yields a larger figure. The correct way is to multiply by 20/120.

Can items with different VAT rates be on the same invoice?

Yes. Each item is calculated at its own rate, and VAT totals broken down by rate are displayed separately at the bottom of the invoice.

Is VAT applied to shipping costs?

Shipping fees reflected on the invoice are generally included in the taxable base. If you have doubts about the applicable rate, ask your financial advisor.

Do I have to do this math manually?

Not when issuing invoices; the software calculates it line by line. Knowing the formula comes in handy when checking incoming invoices and setting prices.

In summary: multiply when going from exclusive to inclusive, divide when going from inclusive to exclusive. Applying a percentage to the inclusive amount is the most common habit that silently generates wrong numbers.

By opening a free account on Qolay.App, you can issue your invoices with the correct rate per line item and monitor your VAT totals from a single screen.

This article is for general informational purposes. VAT rates and implementation principles may change; consult your financial advisor for your specific situation and base your actions on official Revenue Administration announcements.