Adding VAT to a price takes one multiplication. At the UK standard rate of 20%, multiply the price before VAT by 1.2 and you have the total. This guide shows the method at every UK rate, how to do it on a phone or in a spreadsheet, and the mistakes that cause wrong quotes and invoices.
Quick answer: price before VAT × 1.2 = price including 20% VAT. For example, £150 × 1.2 = £180. The VAT is £30.
Method 1: Work out the VAT, then add it
This two-step method is the easiest to follow and shows you the VAT figure separately, which you need for invoices.
- Work out the VAT: multiply the price before VAT by the rate as a decimal. At 20%, that's × 0.2.
- Add it on: add the VAT to the original price.
Example at 20%: £150 × 0.2 = £30 VAT. £150 + £30 = £180.
Method 2: Multiply in one step
If you only need the total, multiply by 1 plus the rate:
| VAT rate | Multiply by | Example: £150 becomes |
|---|---|---|
| 20% standard | 1.2 | £180.00 |
| 5% reduced | 1.05 | £157.50 |
| 0% zero rate | 1 (no change) | £150.00 |
| Any rate r% | 1 + r/100 | £150 × (1 + r/100) |
Worked examples at 20%
| Price before VAT | VAT (× 0.2) | Total (× 1.2) |
|---|---|---|
| £9.99 | £2.00 | £11.99 |
| £45.00 | £9.00 | £54.00 |
| £125.00 | £25.00 | £150.00 |
| £399.00 | £79.80 | £478.80 |
| £2,750.00 | £550.00 | £3,300.00 |
The first row shows rounding in action: £9.99 × 0.2 = £1.998, which rounds to £2.00. VAT is normally rounded to the nearest penny.
How to add VAT on a calculator or phone
- Type the price before VAT, for example 150.
- Press ×, then type 1.2.
- Press =. The answer, 180, is the price including VAT.
Some calculators let you type 150 + 20%, which also gives 180 — but the percentage key works differently between models, so × 1.2 is more reliable. Our guide to working out VAT on a calculator covers the keys in detail.
How to add VAT in Excel or Google Sheets
If the price before VAT is in cell A2:
- VAT amount: =ROUND(A2*0.2,2)
- Price including VAT: =A2+ROUND(A2*0.2,2)
To keep the rate flexible, put it in its own cell (say B1, containing 20%) and use =ROUND(A2*$B$1,2). When a rate changes, you only update one cell. The ROUND function keeps the VAT to whole pennies, so your totals match your invoices.
Adding VAT to several items
When an invoice has several lines, you can work out VAT on each line and add them up, or add up the lines and work out VAT on the total. HMRC accepts either, as long as you're consistent, but they can differ by a penny or two because of rounding.
If different lines have different rates — for example a 20% service and a 0% book — you must work out the VAT separately for each rate. The VAT Invoice Calculator does this and shows the VAT at each rate.
Common mistakes when adding VAT
1. Adding VAT to a price that already includes it
If a supplier's price is already VAT inclusive, adding 20% again overcharges your customer. Check whether a figure says "inc VAT" or "+ VAT" first. Our guide to VAT inclusive vs exclusive prices explains how to tell.
2. Adding VAT when you're not VAT registered
You can only charge VAT if you are registered for VAT. If you're not, your prices shouldn't include a VAT line. Check whether you need to register with the VAT Registration Calculator.
3. Using the wrong rate
Most things are 20%, but some are 5% or 0%. Children's car seats are 5%; most food, books and children's clothes are 0%. See the full list on our UK VAT rates page.
4. Using the "add" method to remove VAT
Adding VAT is multiplication; removing VAT is division. If you have a VAT-inclusive total and want the price before VAT, divide by 1.2 — don't subtract 20%. See how to work out VAT backwards.
Frequently asked questions
What is 20% VAT on £100?
£20. The total including VAT is £120.
How do I add 5% VAT?
Multiply the price by 1.05. For example, £80 × 1.05 = £84, of which £4 is VAT.
Is VAT added before or after a discount?
After. Take the discount off first, then work out VAT on the discounted price.
Is VAT added to delivery charges?
Usually, yes. Delivery normally follows the VAT rate of the goods being delivered, so delivering standard-rated goods is normally charged at 20%.
Do it instantly
Enter any amount in the VAT Calculator with Add VAT selected. It gives the price before VAT, the VAT and the total, with the working shown underneath.
Official source: GOV.UK: VAT rates.