VAT guide

How to Use the VAT Calculators: A Step-by-Step Guide

Choose the correct tool, enter the right figures and understand the results.

Published September 26, 2026 · Updated September 26, 2026

Choose the task first

Use VAT Calculator for a single price, Reverse VAT for a price that already includes tax, and Invoice Calculator for several lines. Choose Threshold for a rolling turnover comparison, Flat Rate for a scheme payment estimate, and Margin Scheme for a qualifying individual resale.

Prepare inputs before typing

Check whether the amount is net or gross. Read the rate from your transaction evidence rather than selecting the default automatically. For margin and profit tools, gather both purchase cost and selling price. Keep all values in pounds and use a decimal point for pence.

Read the breakdown

Each tool displays labelled results and a short calculation explanation. Change one input at a time to understand its effect. On the interactive price graphic, the net £100 stays fixed as the illustrative tax rate changes; this makes the relationship between net, VAT and gross visible.

Use and verify the result

Copy the figures into your own worksheet or accounting process. Reloading resets the calculator, and no submission is made to HMRC. For a manual check, follow the worked example on the calculator post. Blank or invalid inputs clear the result rather than keeping an old answer visible.

Explore the numbers

One price. Three parts.

Move the rate slider to see how VAT changes a £100 net price.

01 / NET£100Before VAT
02 / VAT£20Added tax
03 / GROSS£120Customer pays

£100 + £20 VAT = £120 total

This slider explains the arithmetic. It does not determine the legal rate for your sale.

Keep learning

Educational information and estimates. These tools do not submit VAT returns or determine the treatment of a specific transaction.