United Kingdom · 2026/27 estimate

UK VAT Add, Remove and Flat-Rate Calculator

Add or remove VAT, inspect net and gross amounts, and compare an optional flat-rate percentage.

What this calculator explains

Adding VAT and removing VAT use different formulas. To add 20%, multiply the net amount by 1.20. To remove 20% from a VAT-inclusive amount, divide by 1.20; subtracting 20% from the gross amount gives the wrong answer.

Flat Rate Scheme mode remains separate from ordinary invoice VAT. It applies the selected sector percentage to VAT-inclusive turnover and explains that eligibility, limited-cost-trader rules and special adjustments may change the amount due.

How the estimate is calculated

For add mode, multiply the net amount by 1 plus the selected VAT rate.
For remove mode, divide the gross amount by 1 plus the selected VAT rate.
Calculate VAT as gross minus net.
For invoice mode, calculate each line using the correct selected treatment and sum rounded outputs according to the implementation rule.
For Flat Rate Scheme mode, multiply VAT-inclusive turnover by the selected official percentage.
Display limited-cost-trader, capital-asset and eligibility warnings where relevant.

Formula

Add VAT: gross = net × (1 + rate); remove VAT: net = gross ÷ (1 + rate); VAT = gross − net

Worked example

At the standard 20% rate, a net amount of £1,000 has £200 VAT and a gross total of £1,200. To remove VAT from £1,200, divide by 1.20 to get £1,000 net, then subtract to find £200 VAT. For a Flat Rate Scheme example, VAT-inclusive turnover of £120,000 at an entered 12.5% sector rate produces an illustrative payment of £15,000 before any eligible discount or special adjustment.

Current rules and configuration notes

The main VAT rates remain 20% standard, 5% reduced and 0% zero rate, subject to the legal classification of the supply.
To remove 20% VAT from a gross amount, divide by 1.20; subtracting 20% from the gross amount is incorrect.
Flat Rate Scheme mode must use the selected business-sector percentage and remain separate from ordinary invoice VAT.

Update requirement: Review VAT rates, Flat Rate Scheme percentages, eligibility thresholds and limited-cost-trader rules whenever HMRC changes them.

Included in the estimate

Add and remove VAT
20%, 5% and 0% rate modes
Net, VAT and gross breakdown
Multiple invoice lines
Flat Rate Scheme percentage model
CSV or invoice-summary export

Not included or not guaranteed

A decision about exempt, outside-scope or zero-rated treatment
VAT registration or deregistration advice
Partial exemption and international VAT
A complete VAT return
Automatic Flat Rate Scheme eligibility

Frequently asked questions

How do I add 20% VAT?

Multiply the net amount by 1.20. The difference between gross and net is the VAT amount.

How do I remove 20% VAT?

Divide the VAT-inclusive amount by 1.20. Do not simply subtract 20% from the gross amount.

What are the main UK VAT rates?

The standard rate is 20%, the reduced rate is 5% and zero-rated supplies use 0%, but classification depends on the supply.

What is VAT-exempt?

Exempt supplies are not the same as zero-rated supplies. The calculator does not classify the transaction; the user selects the treatment based on official guidance.

How does the Flat Rate Scheme work?

An eligible business uses a sector percentage on VAT-inclusive turnover and normally cannot reclaim most input VAT, with limited exceptions.

Can I use the calculator for an invoice?

Yes for arithmetic, but invoice-date, tax-point, rounding and record requirements still need to be followed.

Official sources

Applicable period: 2026-04-06/2027-04-05 · Last reviewed: September 3, 2026

Save the calculation with the invoice

Export net, VAT, gross, selected rate and calculation mode so the arithmetic can be reviewed later.

CTA destination: /uk/business/vat-calculator/