The employee is first processed, ignoring any payments which are to be grossed up, to give a net pay. The first payment to be grossed up is added to the net pay, to provide a 'target' net to be achieved.

The payment has an 'estimate' of its gross value made, and the whole employee is then re-processed, altering the estimate, until the net pay is the same as the target net.

The procedure is repeated for each such payment. There is no limit to the number of these payments.

It is also possible to specify that some elements to be grossed-up should be processed before all normal elements, enabling the amount needed to gross up to be reduced, due to the nature of tax and National Insurance bands.

There can be a combination of 'priority' and 'non-priority' gross-up elements. Non-priority elements are always processed in pay element order, after the normal elements.

The priority is controlled in Processing Control Fields.

Note: Employees with payments to be grossed-up take longer to process because the calculate is being repeated several times for each payment.