VAT calculator for the UK

Add VAT to a price, or take it out of a total.

The calculator takes 20%, 5% or 0%. Each figure is rounded to the nearest penny, and a half penny rounds up.

Work out
VAT rate
VAT
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Total with VAT
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Worked out on this page. Nothing you type is sent or kept.

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What the calculator works out

The calculator works one of two ways. “VAT to add” takes an amount before VAT and gives the VAT and the total with VAT. “VAT inside a total” takes a total that includes VAT and gives the amount before VAT and the VAT in it.

An amount can have commas and up to two decimal places.

How each figure is worked out

VAT is charged on the price before VAT. “VAT to add” multiplies the amount by the rate, rounds the VAT to the penny and adds it on.

HMRC’s way to take VAT out is to divide the price including VAT by 1.2 at 20%, or by 1.05 at 5%. “VAT inside a total” does that, rounds the amount before VAT to the penny and takes the rest as the VAT, so the two always add up to the total.

  • £437.63 before VAT at 20%: the VAT is £87.526, which rounds to £87.53. The total is £525.16.
  • £150.10 before VAT at 5%: the VAT is £7.505, which rounds up to £7.51. The total is £157.61.
  • £1,000 including VAT at 20%: 1,000 divided by 1.2 is 833.333 to three places, so the amount before VAT is £833.33 and the VAT is £166.67.

VAT rates for building work in the UK

The law rates a supply by what is supplied. HMRC’s VAT Notices 708 and 708/6 set out these rates for building work in the UK:

  • 20%: repair, maintenance and improvement of an existing building, and most goods.
  • 5%: renovating a home that has been empty for at least two years, and converting a building into a different number of homes.
  • 0%: building a new home.
  • 0%: installing qualifying energy-saving materials in a home, such as insulation, solar panels, heat pumps and batteries, until 31 March 2027. From 1 April 2027 the rate is 5%.

The same arithmetic on a quote or an invoice

A business registered for VAT starts with the calculator’s three rates, in Settings under Tax: a Standard rate of 20%, a Reduced rate of 5% and a Zero rate of 0%.

On a quote or an invoice for work in the UK that charges VAT, the Part of the supply lines are at the Standard rate, unless a line or the kind of work states another Supply rate. Their VAT is worked out once, on their total, and rounded as “VAT to add” rounds it. A line set to Separate, standard rate, Separate, reduced rate or Zero rated is charged 20%, 5% or 0%, worked out on that line alone.

A price list that includes VAT

A price list can come in through Import, in Settings, with a Price, including VAT column. Each price has the VAT taken off at the rate its row names, or else at the rate chosen in VAT the prices include.

The price before VAT is rounded exactly as “VAT inside a total” rounds it, and How the file was read counts those rows as Prices with VAT taken off. A business not registered for VAT keeps the prices as written.

Questions, answered.

Why is the VAT in a total not 20% of the total?
A total of £120 holds £100 before VAT and £20 of VAT. So the VAT in a total is one sixth of it at 20%, and one twenty-first at 5%. HMRC calls this the VAT fraction.
Why can taking VAT out and adding it back miss by a penny?
£99.99 including VAT at 20% is £83.33 before VAT and £16.66 of VAT. Adding 20% to £83.33 gives £16.67 of VAT and a total of £100.00. Each figure is rounded to the penny, so a round trip can end a penny away.
Can a price be typed including VAT?
No. The price is typed before VAT in Unit price, ex VAT on a quote line, Unit price ex VAT on an invoice line and Sold at, ex VAT for a part in the price book. The VAT is then added on the quote or invoice.
Does the office state the VAT under the domestic reverse charge?
Yes. A reverse-charged invoice from the office charges no VAT and states “VAT to be accounted for by the customer”. That figure is worked out as “VAT to add” works it out, once on the lines at 20% and once on the lines at 5%, and the two are added.
Does the office tell me when I have to register for VAT?
No. Nothing in the office counts your turnover against HMRC’s threshold. Since 1 April 2024 you must register once your VAT taxable turnover for the last twelve months goes over £90,000, or when you expect it to go over £90,000 in the next thirty days alone.

Read next.

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