How to add VAT
For a net price N and a percentage rate r, the VAT amount is N × r / 100. The gross price is N × (1 + r / 100). The net amount is the price before this tax is added.
Example: a net price of 100 at an entered rate of 20% produces 20 in VAT and a gross price of 120. The calculator uses currency-neutral amounts so the same arithmetic works in your chosen currency.
How to remove VAT correctly
To recover a net price from a gross price G, divide: N = G / (1 + r / 100). Then subtract the net amount from the gross amount to find the VAT.
For 120 including VAT at 20%, the net amount is 120 / 1.20 = 100 and VAT is 20. Subtracting 20% of 120 would give 96, which is incorrect because the rate applies to the net amount.
Rates and rounding
The entered rate is your assumption. This tool does not look up rates, determine exemptions, or decide how a transaction should be treated. Confirm the rate and treatment that apply to the goods, services and location.
At a zero rate the net and gross amounts are equal. Calculations keep full precision internally and display amounts to two decimal places; invoice systems may round by line or by invoice, creating small differences.