&lt;p&gt;The&amp;nbsp;Sales Tax&amp;nbsp;(included) Method&amp;nbsp;is similar to the Sales Tax (added)&amp;nbsp;method, but instead of adding sales tax to the sub total, the system will separate the already included tax from the sub total.&lt;/p&gt;
&lt;p&gt;You need to enable the &lt;strong&gt;Use &quot;Sales Tax (included)&quot; Method (VAT)&lt;/strong&gt; option in the Tax Configuration page in order for this function to work.&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;If you don&#039;t see any values in the first drop down list (&lt;strong&gt;firstname&lt;/strong&gt;), please see the Registration Form section to configure the form.&lt;/li&gt;
&lt;li&gt;Select the value in the first drop down list.&lt;/li&gt;
&lt;li&gt;Select the value in the second drop down list (operand).&lt;/li&gt;
&lt;li&gt;Enter the value that would be matched to the customer&#039;s entered value. The system will only work correctly if the value is an exact match. We recommend that you should use a drop down type for this form field, so that customers are only able to select the value that you have entered here, instead of entering their data into a field.&lt;/li&gt;
&lt;li&gt;Enter the percentage value.&lt;/li&gt;
&lt;li&gt;Click on the&amp;nbsp;&lt;strong&gt;SUBMIT&lt;/strong&gt; button to add the new Tax criteria.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;The system uses the following formula to calculate the VAT.&lt;br /&gt;&lt;br /&gt;Total Tax = A1 &amp;ndash; A1 / (100% + A2)&lt;br /&gt;A1 = order sub total cost&lt;br /&gt;A2 = tax percentage &lt;br /&gt;&lt;br /&gt;e.g &lt;br /&gt;A1 = $100 &lt;br /&gt;A2 = 8.5 % &lt;br /&gt;Total tax = 100 &amp;ndash; 100 / (100% + 0.085) = 100 - 100 (1 + 0.085) = $7.83&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;