Irish Calculators
VAT & tax arithmetic

VAT Calculator: Add or Remove VAT at Your Rate

Enter a net or VAT-inclusive amount and the rate applicable to your transaction. The tool calculates the price breakdown; it does not choose the legal rate, prepare a VAT return or decide recoverability.

Runs privately in your browserMethod reviewed

Your numbers

€
%
Check the applicable rate and transaction date. This calculator does not classify goods or services.
Your figures stay on this device.

How the calculation works

The VAT tool keeps the before-VAT amount, VAT component and inclusive total together. It uses one percentage supplied by you and a cent-balancing method so the displayed net and VAT amounts add back to the gross total.

Gross = net × (1 + VAT rate/100). Net = gross ÷ (1 + VAT rate/100). VAT = gross − net.

  1. Round the entered amount to cents

    The calculation establishes the amount in integer cents. This fixes the monetary base before computing the corresponding net or gross figure.

  2. Apply the percentage in the correct direction

    Adding VAT multiplies net by one plus the decimal rate. Removing VAT divides gross by the same factor; it does not subtract that percentage directly from gross.

  3. Balance the VAT component

    The remaining difference between rounded gross and net is VAT. This ensures net plus VAT equals the inclusive total after the cent rounding used here.

Worked example: Add 23%

Sample inputs demonstrate the method. They are not a forecast or product offer.

The first example starts with €100 net and an entered rate of 23%. Multiplication by 1.23 produces €123 gross. The €23 balancing difference is VAT, and the three displayed amounts reconcile exactly.

Amount (€)
100
VAT rate (%)
23
Amount entered
Net: add VAT

Expected result

Amount including VAT
€123.00
Worked example: Remove 23%

Sample inputs demonstrate the method. They are not a forecast or product offer.

Amount (€)
123
VAT rate (%)
23
Amount entered
Gross: remove VAT

Expected result

Amount excluding VAT
€100.00

Understanding your result

Read all three figures to check an invoice or compare a net quote with an inclusive budget. A zero VAT amount describes the arithmetic only, not the legal treatment of the supply.

Zero-rated and exempt transactions can have different consequences beyond the price calculation. This page does not determine registration obligations, recoverability, reverse charge or the rate that applies.

Questions you might have

What does this vat calculator include?

Add VAT to a net amount or remove VAT from a VAT-inclusive price using the rate applicable to your transaction.

Which assumptions should I check?

23% is an editable example rate, not a determination of the rate for your supply. Exempt and zero-rated supplies have different legal treatment even though the arithmetic may be zero. The input and calculated net/tax totals use cents; VAT is the balancing difference so net plus VAT equals gross. Calculate invoice lines separately if your accounting policy rounds per line.

Choosing the right inputs

VAT rate
Check the relevant supply and transaction date before entering a rate. The pre-filled 23% is an editable example, not a classification of your goods or services.
Amount entered
Choose net to add VAT or gross to remove VAT already included in a price. Selecting the wrong direction applies tax to the wrong base.
Amount
Enter the amount for one calculation. Where invoice policy rounds VAT separately by line, calculate those lines separately rather than assuming the summed invoice will round identically.

Common mistakes to avoid

  • Do not add VAT again to a shop price already stated as inclusive.
  • Mixed-rate purchases require separate calculations; a single blended guess can hide the correct VAT for each item.

Assumptions to check

  • 23% is an editable example rate, not a determination of the rate for your supply. Exempt and zero-rated supplies have different legal treatment even though the arithmetic may be zero. The input and calculated net/tax totals use cents; VAT is the balancing difference so net plus VAT equals gross. Calculate invoice lines separately if your accounting policy rounds per line.

Sources and method

Read our calculation and testing approach.