UK VAT Calculator (Add or Remove VAT at 20%, 5% or 0%)

This calculator adds VAT to a net price or removes it from a gross price, at the standard rate of 20%, the reduced rate of 5%, or the zero rate. It also checks a turnover figure against the registration and deregistration thresholds.

The single most common VAT error is treating the two directions as symmetrical. Adding 20% and then removing 20% does not return you to where you started, and the section below explains why.

Adding VAT to a net amount is straightforward multiplication:

Removing VAT from a gross amount uses the VAT fraction, because the VAT is a proportion of the gross rather than of the net:

At the standard rate that fraction is 0.2 / 1.2, which simplifies to one sixth. At the reduced rate it is 0.05 / 1.05, or one twenty-first.

Threshold check. If a turnover figure is entered, it is compared against two separate thresholds: registration is required once rolling 12-month taxable turnover exceeds £90,000, and deregistration becomes permissible once expected turnover falls below £88,000. The gap between them is deliberate, so that businesses hovering near the line are not forced to register and deregister repeatedly.

Adding 20% to £1,000 net:

• VAT: £1,000 × 20% = £200.00
• Gross: £1,000 + £200 = £1,200.00

Removing 20% from £1,000 gross:

• VAT: £1,000 × 1/6 = £166.67
• Net: £1,000 − £166.67 = £833.33

Note the asymmetry. £200 and £166.67 are both correct, for different questions. If you take £1,200 gross and remove VAT, you get exactly £200 back and return to £1,000 net, as expected.

Reduced rate, removing 5% from £1,000 gross:

• VAT: £1,000 × 0.05/1.05 = £47.62
• Net: £952.38

• Which rate applies to which supply. Classification is the hard part of VAT and this calculator does not attempt it. Zero-rating, exemption and the reduced rate have detailed and sometimes counterintuitive boundaries.
• Exempt and outside-the-scope supplies. Exempt is not the same as zero-rated: zero-rated supplies count toward taxable turnover for registration and allow input VAT recovery, exempt supplies do not.
• The Flat Rate Scheme, under which a business pays a fixed percentage of gross turnover instead of accounting for input and output VAT separately.
• Partial exemption, the Capital Goods Scheme, the Cash Accounting Scheme and the Annual Accounting Scheme.
• Input VAT recovery. This calculates VAT on a single amount, not a VAT return position.
• The reverse charge, which applies to certain construction services and cross-border supplies.
• Northern Ireland's position under the Windsor Framework for goods moving to and from the EU.

• Dividing a gross price by 1.2 and then subtracting, versus multiplying by 1/6. These give the same answer, but subtracting 20% of the gross does not. £1,000 minus 20% is £800, which is wrong by £33.33.
• Assuming zero-rated and exempt are interchangeable. A zero-rated business can reclaim input VAT and must count that turnover toward the £90,000 threshold. An exempt business generally cannot reclaim input VAT and its exempt turnover does not count.
• Using the registration threshold to decide when to deregister. They are different figures, £90,000 and £88,000, and using the wrong one leads to deregistering too early.
• Forgetting that the registration test is a rolling 12-month test, not a financial-year test. It can be triggered part way through a year, and there is also a forward-looking test if turnover is expected to exceed the threshold within the next 30 days alone.
• Rounding VAT per line rather than per invoice, which can produce small discrepancies against a supplier's own calculation.

• GOV.UK: "VAT rates on different goods and services" -- gov.uk/vat-rates
• GOV.UK: "VAT registration: when to register" -- registration threshold £90,000
• GOV.UK: "VAT: increasing the registration and deregistration thresholds" -- deregistration threshold £88,000, both effective 1 April 2024
• All figures verified on 30 August 2026 and mirrored in engine/tables/2026/uk-2026-27.json