For any type of child maintenance arrangement, either parent can use the free online calculator (opens in new tab)

To use the calculator, you will need to know the paying parents income before tax and after pension contributions.

Both the CMS online calculator and the CMS calculation decision after application are based on a number of factors that include:

• The paying parent’s income before tax and after pension contributions

• The number of overnight stays the child/young person has with the paying parent

• Any other children that the paying parent may be responsible for (including all children the paying parent lives with).

Child maintenance is calculated over 12 -month period and divided into weekly or monthly payments.

Further Information on CMS calculations (opens in new tab)

There are instances where paying parents are exempt from paying child maintenance these include when the paying parent:

• Is a student with no income

• Is in prison

• Is deceased

• Has a court ordered child payment arrangement that has been in place for less than 12 months.

The online calculator provides an estimate only. If you apply to the CMS, the amount may be different.

Although the number of overnight stays is taken into consideration when calculating payments, it is important to note that child maintenance and child contact arrangements are separate legal issues. Children’s rights and the wellbeing of the child should be central to all decision making and parents should seek legal advice should any issues arise with contact arrangements.