VAT. Short for Value Added Tax — though many small business owners, upon encountering it for the first time, might suggest it stands for something considerably more colourful. It's one of those taxes that sounds straightforward but has just enough wrinkles to catch people out. This guide covers everything you need to know to handle VAT correctly, confidently, and without any unpleasant surprises from HMRC.
What Is VAT?
VAT is a consumption tax added to the sale price of goods and services. In the UK, the standard rate is 20%. There's also a reduced rate of 5% (for things like domestic energy and children's car seats) and a zero rate of 0% (for most food, books, and children's clothing). Businesses collect VAT on behalf of HMRC and pass it on — you're essentially an unpaid tax collector.
Our VAT calculator handles adding and removing VAT in seconds — much easier than doing the maths manually, especially when you're mid-invoice.
Adding VAT to a Price
To add 20% VAT to a net (pre-VAT) price, multiply by 1.20.
- Net price: £100
- VAT at 20%: £100 × 0.20 = £20
- Gross (VAT-inclusive) price: £120
Simple enough. The number on your invoice to customers is the gross figure. If you're VAT registered, you need to show the VAT element separately on your invoice.
Removing VAT from a Price (The Bit People Get Wrong)
Here's where many people make a mistake. If you have a VAT-inclusive price and want to find the net amount, don't multiply by 0.80. Instead, divide by 1.20.
Why? Because the 20% VAT is calculated on the net price, not the gross. So:
- Gross price: £120
- Net price: £120 ÷ 1.20 = £100
- VAT element: £120 − £100 = £20
If you incorrectly multiply £120 by 0.80, you get £96 — which is wrong. It's a small error that accumulates significantly over hundreds of transactions. Use our online VAT calculator to remove this source of human error entirely.
Do You Need to Register for VAT?
You must register for VAT if your taxable turnover exceeds £90,000 in any 12-month rolling period (this is the 2025/26 threshold — check GOV.UK for the latest). You can also register voluntarily below this threshold, which can make sense if:
- Your customers are mostly VAT-registered businesses (they can reclaim VAT, so the price to them is the same)
- You have significant VAT on your own purchases that you'd like to reclaim
- You want to appear more established
If your customers are primarily consumers (individuals who can't reclaim VAT), registering voluntarily when you don't have to effectively makes your prices 20% more expensive — or squeezes your margin.
Input VAT and Output VAT
Once registered, you charge output VAT on your sales and pay input VAT on your purchases. Every quarter (in most cases), you file a VAT return with HMRC. If your output VAT exceeds your input VAT, you pay the difference to HMRC. If your input VAT exceeds your output (common for businesses with high costs), HMRC repays you. This is one of the benefits of VAT registration for businesses with significant expenses.
Flat Rate Scheme: A Simpler Option
For businesses with a turnover below £150,000, HMRC offers the Flat Rate Scheme. Instead of calculating exact VAT on every transaction, you pay a fixed percentage of your gross turnover to HMRC (the rate depends on your industry). For some businesses this is simpler and can even be marginally more profitable — but it's not always better. Run the numbers for your specific situation before choosing.
Common VAT Mistakes to Avoid
- Charging VAT when not registered: Illegal. Only VAT-registered businesses can charge VAT.
- Using the wrong rate: Some goods are zero-rated or reduced-rated — check if your products qualify.
- Late VAT returns: HMRC applies a penalty points system and surcharges for late filing and payment.
- Not keeping receipts: You can only reclaim input VAT if you have a valid VAT invoice from the supplier.
VAT isn't complicated once you understand the fundamentals — but those fundamentals genuinely matter. Get them right and it's a perfectly manageable part of running a business.
Further reading: HMRC's GOV.UK pages have detailed VAT guidance for every business type. Read HMRC's official VAT registration guidance.