How to Add or Remove VAT from a Price (With Formulas)
Learn the simple formulas to add VAT to a net price or remove it from a gross price, avoid the common subtraction mistake, and round amounts correctly.
If you sell products, send quotes to clients, or just want to check a receipt, you’ll often need to work out how much of a price is tax. Sometimes you have a price before tax and need the total a customer pays. Other times you have a total that already includes tax and need to split it into the base price and the tax.
The math is simple once you know the two formulas, but one shortcut gives the wrong answer and many people use it. This guide explains both calculations with examples, shows the mistake to avoid, and covers rounding and how to show tax on invoices and quotes. It’s a general explanation of the arithmetic, not tax advice. Rules about which rate applies and how amounts must appear on documents depend on where you are and what you sell.
Net, gross and VAT: the three numbers
A few terms first:
- Net price: the price before tax. You may also see it called “excluding VAT” or “ex. VAT.”
- Gross price: the price after tax is added. You may also see “including VAT” or “inc. VAT.”
- VAT amount: the tax itself, which is the difference between gross and net.
VAT (value-added tax) is a consumption tax used in many countries. Sales tax, GST and similar taxes work the same way for these calculations. You apply a percentage rate to the net price. In the formulas below, the rate is written as a decimal, so 20% becomes 0.20 and 7.5% becomes 0.075.
How to add VAT to a net price
When you know the net price, adding tax takes one multiplication:
- VAT amount = net × rate
- Gross price = net × (1 + rate)
Example at a 20% rate: a net price of 250.00
- VAT = 250 × 0.20 = 50.00
- Gross = 250 × 1.20 = 300.00
The “1 +” part keeps the original price and adds the tax in the same step. At a 10% rate you multiply by 1.10. At 5% you multiply by 1.05.
How to remove VAT from a gross price
This is the direction where people make mistakes. When the price already includes tax, you divide by (1 + rate). You don’t subtract the rate.
- Net price = gross ÷ (1 + rate)
- VAT amount = gross − net, which is the same as gross × rate ÷ (1 + rate)
Example at a 20% rate: a gross price of 300.00
- Net = 300 ÷ 1.20 = 250.00
- VAT = 300 − 250 = 50.00
This takes you back to the numbers from the previous example, which shows the method is right.
The common mistake: subtracting the rate from the gross
The tempting shortcut is to take 20% off the gross price. It gives the wrong answer, because the 20% was calculated on the net price, not the gross. The gross is larger than the net, so 20% of the gross is more than the tax that was actually added.
| Gross price (20% rate) | Wrong: gross × 0.80 | Right: gross ÷ 1.20 | Error |
|---|---|---|---|
| 120.00 | 96.00 | 100.00 | 4.00 too low |
| 300.00 | 240.00 | 250.00 | 10.00 too low |
| 1,200.00 | 960.00 | 1,000.00 | 40.00 too low |
The error grows with the price and with the rate. At low rates the wrong answer looks close enough to pass unnoticed, which is why the mistake is so common. To check any result, add the tax back to your net figure. If you don’t get the original gross, something is wrong.
Quick reference: which formula to use
| You have | You want | Formula |
|---|---|---|
| Net price | VAT amount | net × rate |
| Net price | Gross price | net × (1 + rate) |
| Gross price | Net price | gross ÷ (1 + rate) |
| Gross price | VAT amount | gross − (gross ÷ (1 + rate)) |
| Net and gross | The rate used | (gross ÷ net) − 1 |
The last row helps when a receipt shows both prices but not the rate. For more general questions like “what percent is X of Y?”, the percentage calculator works too: pick the question that matches what you want to know, enter the two numbers, and read the result. It updates as you type.
How to add or remove VAT with Deftivo
If you don’t want to type formulas into a spreadsheet, the Deftivo VAT calculator does both directions. It works with any rate, so you can use it for VAT, sales tax or GST. The calculation runs in your browser.
- Set the VAT or sales tax rate. Enter the percentage that applies to your sale.
- Enter a net price to add VAT, or a gross price to remove it. Use the field that matches the price you have.
- Read the tax and the other amount. The tool shows the tax amount and either the gross or the net price, depending on what you entered.
To check your work, put the result back in the opposite direction. The net figure it gives you should produce your original gross price.
Rounding: where the cents go
Most currencies are shown to two decimal places, but VAT calculations often produce longer numbers. For example, 99.99 ÷ 1.20 = 83.325. How you round can change the result by a cent or two.
- Round at the end, not in the middle. Keep full precision while you calculate and round only the final figures.
- Per line or per total? An invoice can calculate VAT on each line and add up the rounded amounts, or add the net amounts first and calculate VAT once on the total. The two methods can differ by a few cents. Choose one and use it every time, and check whether local rules or your accounting software require a particular method.
- Make the numbers add up. On any document, net + VAT should equal gross exactly. If rounding causes a one-cent gap, it’s usually safer to calculate VAT as gross minus net than to round each figure on its own.
Invoices and quotes
When you send a price to someone, make it clear whether tax is included. A quote that just says “1,500” can lead to an argument later if the client thought the tax was included and you didn’t.
Good practice:
- Label prices clearly as excluding VAT or including VAT.
- Show the net amount, the rate, the VAT amount and the gross total as separate lines.
- If you use more than one rate, for example when some items are taxed at a reduced rate, show a subtotal for each rate.
- Business customers often think in net prices, while consumers usually expect prices with tax included. Write the quote for the person reading it.
What an invoice must contain legally varies by country, so check with your local tax authority or an accountant.
Tips and pitfalls
- Discounts and VAT: a percentage discount gives the same gross total whether you apply it before or after tax, because both are just multiplications. A fixed-amount discount, such as “50 off,” is different. Taking 50 off the net price saves the customer more than taking 50 off the gross. The discount calculator helps with sale prices, discount percentages and stacked discounts.
- Don’t add tax twice. If a supplier’s price already includes tax, removing it first avoids charging tax on tax.
- Watch the rate format. 20% is 0.20, not 20 and not 0.02. Getting this wrong is a common spreadsheet error.
- Use the right rate. Many places have standard, reduced and zero rates for different goods and services. The calculation is only correct if the rate is.
FAQ
Why can’t I just subtract the tax percentage from the total?
The tax percentage was calculated on the net price, and the total is a larger number. Taking the same percentage off the total removes too much. Divide the total by (1 + rate) to get the correct net price.
Does the Deftivo VAT calculator only work for one country?
No. You set the rate yourself, so it works for any VAT, sales tax or GST percentage. Check which rate applies to your situation before you calculate.
Should I round VAT per item or on the invoice total?
Both methods are used, and they can differ by a cent or two. Choose one and apply it every time, and make sure net plus VAT always equals the gross total. If you’re unsure which method applies to you, check your local rules or ask an accountant.
How do I find the tax rate if I only know the net and gross prices?
Divide the gross by the net and subtract 1. For example, 330 ÷ 300 = 1.10, so the rate is 10%. This is a quick way to check the rate printed on a receipt or invoice.