How Is Child Maintenance Calculated in the UK?

What Is Child Maintenance? 

Child maintenance is money paid by one parent to the other to help cover the costs of raising a child. It contributes to essentials such as food, clothing, school costs, and other everyday needs. 

Who Decides the Amount? 

In the UK, there are two main ways child maintenance can be arranged: 

1. Family-based agreements – Parents agree privately how much will be paid. 
2. Child Maintenance Service (CMS) – If parents cannot agree, the government’s CMS calculates it. 

Even if you go through CMS, parents are encouraged to try a private agreement first. 

How the Child Maintenance Service Calculates Payments 

The CMS uses a simple formula based on the paying parent’s gross income, the number of children, and the child’s living arrangement. Here’s a basic overview: 

Gross weekly income
The CMS looks at your total income before tax.

Number of children
Payments increase with each child:

• 1 child: 12% of gross weekly income
• 2 children: 16%
• 3 or more children: 19%

Other children
If the paying parent has children in a different household, the percentage is slightly reduced.

Shared care
If the child spends time with both parents, the payment may be reduced depending on the number of nights spent with the paying parent.

Example: 

If a parent earns £500 per week before tax and has one child, the CMS might calculate:
£500 × 12% = £60 per week 

If the child spends time with both parents, this may be reduced proportionally. 

Other Factors That May Affect Payments 

• Income changes – If the paying parent’s income rises or falls, payments can be adjusted. 
• Special needs – Children with additional needs may require extra support. 
• Other agreements – Some parents have arrangements outside CMS that can be formalised legally. 

Why Professional Advice Helps 

Child maintenance can get complicated, especially when: 

• You have multiple children or households 
• Income varies 
• There are disputes over shared care or special needs 

A solicitor can help negotiate the amount of child maintenance to be paid, with a view to agreeing on an arrangement that is fair and avoids future disputes.