If you run a UK business that is registered for VAT, you need to know how to calculate the tax correctly. Get it wrong and you either underpay HMRC (triggering interest and penalties) or overcharge your customers (making your prices uncompetitive).
This guide covers the three main VAT rates used in the UK, the exact formulas for adding and removing VAT, and how to handle exports. We will use real numbers throughout so you can follow the maths yourself.
When Do You Need to Calculate VAT?
You must register for VAT if your VAT taxable turnover exceeds £90,000 in any rolling 12-month period [1]. You can also register voluntarily if your turnover is below that threshold [1]. Once registered, you must include VAT at the correct rate on all goods and services you supply [1].
You then report the VAT you charged customers and the VAT you paid to suppliers by sending a VAT return to HMRC, usually every three months [1]. The amount you pay HMRC is typically the difference between the VAT you collected and the VAT you paid out [1]. If you collected more than you paid, you send the difference to HMRC. If you paid more than you collected, HMRC refunds you.
The Three Main VAT Rates in the UK
There are three rates you will encounter day to day:
- Standard rate (20%), applies to most goods and services.
- Reduced rate (5%), applies to specific items like domestic fuel, children's car seats, and some home renovations.
- Zero rate (0%), applies to exports, most food, children's clothing, books, and public transport.
There is also a small number of exempt supplies (such as insurance and education) where you do not charge VAT and cannot reclaim input VAT on related costs. Exempt is not the same as zero-rated. If you only make exempt supplies, you cannot register for VAT at all.
How to Add VAT to a Price (Working Out the VAT-Inclusive Price)
If you sell goods or services and need to add VAT, you multiply the price excluding VAT by the appropriate factor.
Adding 20% VAT (Standard Rate)
Multiply the price excluding VAT by 1.2 [2].
Example: You sell a chair for £60 excluding VAT. The price including VAT is £60 x 1.2 = £72 [2]. The VAT element is £12.
Adding 5% VAT (Reduced Rate)
Multiply the price excluding VAT by 1.05 [2].
Example: You sell a child's car seat for £200 excluding VAT. The price including VAT is £200 x 1.05 = £210 [2]. The VAT element is £10.
Zero-Rated Supplies (0%)
You do not add any VAT. The price stays the same. You still record the sale on your VAT return, but the VAT amount is £0.
How to Remove VAT from a Price (Working Out the VAT-Exclusive Price)
If you have a total price that includes VAT and need to find the amount before VAT, you divide by the appropriate factor.
Removing 20% VAT
Divide the price including VAT by 1.2 [2].
Example: You bought a table and the total price including 20% VAT was £180. The price excluding VAT is £180 ÷ 1.2 = £150 [2]. The VAT you can reclaim is the difference: £30.
Removing 5% VAT
Divide the price including VAT by 1.05.
Example: A domestic fuel bill comes to £210 including 5% VAT. The price excluding VAT is £210 ÷ 1.05 = £200. The VAT element is £10.
How to Calculate the VAT Amount Only
Sometimes you just need the VAT figure itself. You can use these shortcuts:
- From a VAT-exclusive price at 20%: Multiply by 0.2. Example: £150 x 0.2 = £30.
- From a VAT-inclusive price at 20%: Multiply by 1/6 (or 0.1667). Example: £180 x 1/6 = £30.
- From a VAT-exclusive price at 5%: Multiply by 0.05. Example: £200 x 0.05 = £10.
- From a VAT-inclusive price at 5%: Multiply by 1/21 (or 0.0476). Example: £210 x 1/21 = £10.
The 1/6 fraction for 20% VAT-inclusive is worth remembering. It is the quickest way to find the VAT on a receipt total.
How to Handle Exports (0% VAT)
Exports of goods to customers outside the UK are generally zero-rated for VAT purposes [3]. That means you do not charge VAT on the sale, but you can still reclaim the VAT you paid on related costs (such as raw materials or packaging).
To apply the 0% rate, you need to keep evidence that the goods left the UK. For exports to EU countries, you must submit the VAT return and documentary package within 180 days from the date the goods were shipped [3]. For exports outside the EU, the 180-day period runs from the date the goods were cleared for export by customs [3].
If you cannot prove the goods were exported within that window, HMRC may treat the sale as standard-rated and you will owe the VAT plus penalties [3].
If you export goods and the sale is priced in a foreign currency, you convert it to sterling using the exchange rate on the date the goods were dispatched, not the date of payment [3].
Common Mistakes When Calculating VAT
Using the wrong divisor. A common error is dividing by 0.2 instead of 1.2 when removing VAT. Dividing £180 by 0.2 gives £900, which is nonsense. The correct divisor is 1.2.
Confusing exempt and zero-rated. Zero-rated supplies are taxable at 0% and let you reclaim input VAT. Exempt supplies are not taxable at all and block input VAT recovery on related costs. If you mix both, you enter partial exemption, which requires a special calculation.
Forgetting the 180-day export deadline. If you export goods and do not collect the right paperwork within 180 days, you risk losing the 0% rate and owing VAT plus penalties [3].
Including VAT in consumer credit income. If your business provides consumer credit, VAT should not be included in the income you report for regulatory purposes [4]. This is a niche point but matters if you are in the credit broking or hire purchase space.
VAT Calculation in Practice: A Worked Example
Let us walk through a typical quarter for a small limited company in Manchester that sells software subscriptions (standard-rated) and exports to the US (zero-rated).
Sales (outputs):
- UK subscriptions: £24,000 excluding VAT. Add 20%: £24,000 x 1.2 = £28,800. VAT charged: £4,800.
- US exports: £8,000. Zero-rated. VAT charged: £0.
Purchases (inputs):
- Cloud hosting (UK): £3,600 including 20% VAT. Remove VAT: £3,600 ÷ 1.2 = £3,000. VAT reclaimable: £600.
- Office supplies: £600 including 20% VAT. Remove VAT: £600 ÷ 1.2 = £500. VAT reclaimable: £100.
- US marketing services: £2,000. No UK VAT charged. VAT reclaimable: £0.
VAT return calculation:
- Total output VAT: £4,800 + £0 = £4,800.
- Total input VAT: £600 + £100 + £0 = £700.
- Net VAT due to HMRC: £4,800 - £700 = £4,100.
The company pays £4,100 to HMRC for that quarter.
When to Use a VAT Calculator Tool
If you process dozens of invoices each month, doing the maths manually is inefficient and error-prone. Most accounting software (Xero, QuickBooks, FreeAgent, Sage) calculates VAT automatically on each transaction and populates your VAT return. You still need to understand the underlying formulas so you can spot mistakes.
We have a VAT calculator on our site that handles the standard and reduced rates. It is useful for quick checks.
Making Tax Digital for VAT
Since April 2022, all VAT-registered businesses must keep digital records and file VAT returns using compatible software. You cannot file directly through the HMRC website anymore. This is part of HMRC's Making Tax Digital (MTD) programme.
If you are not yet using MTD-compatible software, you need to switch. Most cloud accounting packages are already compliant. For more detail, see our VAT and Making Tax Digital guide.
What Happens If You Get the Calculation Wrong?
HMRC charges interest on late or underpaid VAT. The current late payment interest rate is set at Bank of England base rate plus 2.5%. There are also penalties for errors, ranging from 0% to 30% of the underpaid tax depending on whether the error was careless or deliberate.
If you discover an error on a past VAT return, you can correct it on the next return if the net error is under £10,000, or under 1% of your turnover (capped at £50,000). Larger errors require a formal amendment.
Getting Professional Help
VAT calculations are straightforward for most businesses with a single rate and simple supplies. But if you deal with mixed supplies, partial exemption, property transactions, or cross-border sales, the rules get more complex. As ICAEW qualified accountants, we handle VAT compliance for businesses across the UK, from sole traders in Bristol to limited companies in Leeds.
If your business has crossed the £90,000 VAT threshold in the last 30 days, you need to register within that 30-day window. Contact us through our contact page to discuss your specific situation.
For a broader overview of UK business taxes, start with our fundamentals page.
Sources
- gov.uk: How VAT works: Overview - GOV.UK
- aka.hmrc.gov.uk: Charge, reclaim and record VAT - GOV.UK
- accaglobal.com: The VAT calculation for export of goods | ACCA Global
- fca.org.uk: Consumer credit income, what to report - FCA